IN
INDIA
A PERSPECTIVE
Rajesh Kochhar & Jayant Narlikar
A DIAMOND JUBILEE PUBLICATION
INDIAN NATIONAL SCIENCE ACADEMY
NEW DELHI
/; -
Astronomy in India
A Perspective
Rajesh Kochhar & Jayant Narlikar
A Diamond Jubilee Publication
Indian National Science Academy
New Delhi
©1995
Indian National Science Academy
Bahadurshah Zafar Marg, New Delhi 1 10 002
Published by the Executive Secretaiy, Indian National Science Academy, New Delhi 1 10002,
and printed by him at Vykat Prints, Airport Road, Bangalore 560017
Foreward
Astronomy is the oldest scientific discipline humankind has known. Being an ancient
culture, India has a long tradition of astronomical and related activities. As present we have no
definite clues to the astronomical knowledge of the Harappan people. Although Rigveda contains
stray astronomical references, the oldest Indian text exclusively devoted to the subject is the
Vedanga Jyotisha , which is generally dated about 1400 BC. This work, mostly attributed to
Lagadha, describes a rather inexact calendar in which a five-year yuga is equated with 1 830 civil
days. (Correct value would be 1826 days plus a fraction.)
Mathematically rigorous, Siddhantic astronomy began in AD 499 with the influential
treatise Aryabhatiya. Ironically, while today we take great pride in Aryabhata’s achievement,
in ancient times he was severely condemned by many for deviating from tradition. During the
Siddhantic phase, instruments and observations played second fiddle to mathematical calcula-
tions. Observational astronomy came to its own in the 14th century when, under the patronage
of Ferozshah Tughlaq, Persian and Arabic Zizes (observational tables) were copied, commented
upon and to an extent Sanskritized. The Zij phase came to an end with Raja Jai Singh Sawai’s
imposing but anachronistic pre-telescopic, masonry observatories built at Delhi and Jaipur during
1721-34.
Modem astronomy came to India in tow with the Europeans, who needed it as a navigational
and geographical aid. Telescopes were sporadically used in India by the English and the French
in the 17th century itself. However, it was in the post-Plassey period that modem astronomy was
officially patronized for reasons of state. An observatory was set up at Madras in 1790, to act as
India’s Greenwich. Along with the botanical garden established at Sibpur near Calcutta in 1787,
the observatory was, in today’s idiom, the first modem research institute in India.
The 20th century saw the fruition of Indian response to modem science. T.P. Bhaskaran
(also known as Bhaskara Sastri) became the first Indian director of Nizamiah Observatory,
Hyderabad, in 1922, and A.L. Narayan of Kodaikanal Observatory in 1937. More importantly,
Indian universities produced epoch-making work. M.N. Saha’s theory of thermal ionization laid
the foundation of theoretical astrophysics, whereas N.R. Sen and V.V. Narlikar initiated research
into theory of relativity. Astronomical sciences were well represented in the Indian National
Science Academy when it was set up in 1935. (It was then known as the National Institute of
Sciences of India. The name was changed in 1970.) Its foundation fellows included Saha, Sen,
Bhaskara Shastri and A.L. Narayan. Another ’astrophysical’ foundation fellow was A.C. Baneiji,
who later became the vice-chancellor of Allahabad University.
Building an astronomical observatoiy in the 18th century was one of the first scientific
acts of the British in India; establishment of the Indian National Science Academy one of the
last. The observatoiy and the Academy between them neatly bracket the institutionalization of
modem science in India under colonial auspices and the consequent emergence of National
Science. It is therefore appropriate that on the occasion of its diamond jubilee the Academy
should bring out a book dealing primarily with modem astronomy in India.
Astronomy and astrophysics in India have come a long way since independence. A number
of astronomical centres have come up that seek to observe the universe in various wavelength
bands, from ground and from space. In addition, theoretical studies are being carried out at various
places. If the universities have not lived up to their early promise, remedial action is being sought
by the establishment of inter-university centres. Indian participation in the worldwide develop-
ment of astronomy has been steadily growing. This is reflected in research publications, in
school, workshop and conference activities and in collaborative research projects between
scientists in this country and abroad. Astronomy and astrophysics form an important component
of the scientific activities overseen by the Indian National Science Academy.
This small book by Rajesh Kochhar and Jayant Narlikar gives a concise account of modem
astronomical facilities in India. This account has been placed in the context of historical
developments in India on the one hand and global state of the art on the other. I hope this book
will appeal to a wide spectrum of readership.
New Delhi
October 1994
S.K. Joshi
President
Indian National Science Academy
Preface
This book gives a brief account of astronomical research in India. Chapter 1 begins with
a resume of pre-telescopic developments and goes on to describe the advent and growth of modem
astronomy in India up to the time of independence. Chapter 2 describes the present research
facilities at various astronomical centres and their future plans. Chapter 3 describes the high-
lights of research programmes in India. Chapter 4 is devoted to promotional activities at
professional, amateur and popular level.
This book draws heavily on a compilation which we brought out on behalf of our
institutions last year ( Astronomy in India: Past, Present and Future). Our task has been rendered
easier by the co-operation we received from our many colleagues, friends and their institutions.
Several of them have contributed by sending relevant material or by reviewing it. We take this
opportunity to thank them. We also thank the Chairman and the members of the National
Committee for the International Astronomical Union for their helpful suggestions. We thank the
Director, Salar Jung Museum, Hyderabad for making available a photograph of a painted sketch
of Lilavati and for permitting us to include it in the present work.
Indian Institute of Astrophysics, Bangalore
Inter-University Centre for Astronomy & Astrophysics, Pune
RajeshKochhar
Jayant Nariikar
Contents
Foreward i
Preface iii
1. Historical perspective 1
2. Astronomical facilities 28
3. Research highlights 53
4. Promotional activities 74
Directory of addresses 79
Index 83
1
Historical perspective
India, as can be expected from an ancient culture, has a long astronomical tradition. The
oldest astronomical text in India is the VedangaJyotisha (astronomy as part of the Vedas), one
part of which is attributed to Lagadha. It is dated about 1400 BC on the basis of the statement
in the book that the winter solstice took place at the star group Shravishtha (Alpha Delphini).
A later astronomer of the same school is Garga who is placed at about 450 BC on the basis of
his observation that 'the sun is found turning [north] without reaching the Shravishthas'. The
earliest interest in astronomy was in observing equinoxes and solstices for ritualistic purposes,
in making rather inexact luni-solar calendars, and in observing conspicuous stars (Nakshatras)
as a guide to the motion of the moon and the sun.
Siddhantic astronomy
The development of mathematical, or Siddhantic, astronomy came about as a result of
interaction with Greece in the post- Alexandrian period. (Siddhanta literally means the estab-
lished end.) The leading figure in this modernization was Aiyabhata I, who was bom in AD 476
and completed his influential work, Aryabhatiya, in AD 499. The main occupation of Indian
astronomers for the next thousand years and more was the calculation of geocentric planetary
orbits and developing algorithms for the solution of the mathematical equations that arose in the
process. Illustrious names in Indian astronomy following Aiyabhata are Latadeva (505) who was
Aryabhata's direct pupil; Varahamihira (c. 505) a compiler rather than a researcher, and an expert
on omens; Bhaskara I (c. 574); Aryabhata's bete noire Brahmagupta (b. 598) whose works were
later translated into Arabic; Lalla (c. 638 ore. 768); Manjula or Munjala (932); Shripati (1039);
and Bhaskara II (b. 1 1 14), the last of the celebrated astronomers (Table 1).
There were also a host of commentators including such well-known names as Prithudaka
(864) in Kannauj, Bhattotpala (966) in Kashmir, and Parameshvara (1380-1460) in Kerala, who
were astronomers in their own right. There were also a number of astronomers whose own work
1
Astronomy in India: A Perspective
is not extant, but they are cited by others. There is an Indian astronomer Kanaka who is unknown
to Indian sources but appears in the Arabic bibliographic tradition as Kanak al-Hindi. He is said
to have been a member of the embassy that was sent from Sind to Baghdad to prepare Zij al-
Sindhind (translation of Brahmagupta's Brahmasphuta-siddhantd ). In the absence of any reliable
information on him^ a large number of legends have grown around him, making him a person-
ification of the transmission of science from India to the Arabs.
In addition to the Siddhantas there are in Sanskrit and allied languages books called
Karanas. If Siddhantas are the text books, Karanas are the made-easy books (Table 2). They
give practical rules for carrying out computations. A noteworthy feature is that Karanas choose
a contemporaneous epoch rather than follow the Siddhantas in starting from a Kalpa or a Yuga.
As early as about AD 1000, A1 Biruni (973-1048) noted that there were innumerable Karana
works. One of the most influential has been Ganesha Daivajna's Graha-laghava (1520). Karana
activity continued right up to the 19th century, and was even sponsored by the British. There are
tertiary texts also associated with Siddhantas and Karanas. They are the Koshtakas or Saranis,
which provided ready-made specialist astronomical tables for use by astrologers and almanac
makers.
Work on observational aspects has been rather limited. Parameshvara made eclipse
observations from 1393 to 1432, and later Achyuta Pisharati (c.1550-1621), also in Kerala,
(c. 1730- 1 800) wrote a four-chapter treatise Uparagakriyakrama on lunar and solar eclipses. In
the 18th century NandaramaMishra (c.1730-1800) prepared a Karana work, Grahana-paddhati,
on eclipses..
The Siddhantic school was mildly influenced by the British presence in India. Indian
assistants at British Indian observatories tried to update Siddhantic elements. Kero Lakshman
Chhatre (1824-84) started his career at Colaba Observatory in 1851, became the professor of
mathematics and natural science at Poona College in 1865, and was made aRao Bahadur in 1877
two years before his retirement In 1860 he brought out in Marathi a handbook Graha-sadhanachi-
koshtake ; based on the 1808 work of R.S. Vince. An assistant at Madras Observatory, Chintamani
Ragoonatha Chany (1828-80), completed his Tamil work Jyotisha-chintamani, and also an
almanac, called Drig-ganita-panchanga, , based on the Nautical Almanac. Many young men from
families with tradition of Sanskrit studies took to modem astronomy. A school teacher V enkatesh
Bapup Ketkar (1854-1930) compiled a modem astronomical almanac Jyotir-ganita in Sanskrit,
with the year 1875 as the epoch. Ketkar is however better known in India for his published
prediction (1911) of the existence of a planet beyond Neptune.
It is a matter of historical curiosity that the last of the classical Siddhantic astronomers
2
Historical perspective
Table 1. Important Siddhantas
Year
Author 1
Place
Work 2
b.476
Aryabhata I
Patna
Aryabhata-siddhanta
Aryahhatiya(499)
c.505
Latadeva
Redactions of Saura-,
Romaka-, Paulisha-siddhantas
c.620-700
Brahmagupta*
Bhillamala,
Rajasthan
Brahma-sphuta-siddhanta (628)
fl.629
Bhaskaral
Valabhi, Gujarat
Maha-bhaskariya (629)
Laghu-bhaskariya
8th cent.
Lalla
Dasapura, Malwa
Shishya-dhi-vriddhida (748)
c.800
Anon.
Surya-siddhanta
b.880
Vateshvara
Vatanagara, N.Gujarat
Vateshvara-siddhanta (904)
c.953
Aryabhata II
Maha-siddhanta
c. 1000-1050
Shripati*
Rohinikhand,
S.ofUjjain
Siddhanta-shekhara
b.1114
BhaskaralF
Vijjalavida,
Bijapur
Siddhanta-shiromani (1150)
b.1444
Nilakantha Somayaji
Kundapura, Kerala
Tantra-sangraha
c. 1475 -1525
Jnanaraja
Parthapura,Godavari
Siddhanta-sundara (1503)
c. 1550-1621
AchyutaPisharati*
Kerala
Sphuta-nimaya-tantra
c. 1600-1660
Nityananda
Kurukshetra
Siddhanta-sindhu (1628)
Siddhanta-raja (1639)
b.1603
Munishvara
Varanasi
Siddhanta-sarvabhauma (1646)
b.1610
Kamalakara
Varanasi
Siddhanta-tattva-viveka (1658)
1835-1904
Chandrashekhar
Simha
Khandapara, Orissa
Siddhanta - darpana (1894)
1 . Asterisk denotes appearance in Table 2 also.
2. The number in bracket after the work is the year of its composition or the epoch chosen for
computations.
3
Astronomy in India: A Perspective
Table 2. Important Karanas
Year
Author 1
Race
Work 2
505
Varahamihira
Ujjain
Pancha-siddhanta
c.620-700
Brahmagupta*
Bhillamala, Rajasthan Khanda-khadyaka (665)
c.650700
Haridatta
Kerala
Graha-chara-nibandhana (683)
c.650-700
Devachaiya
Kerala
Karana-ratna(689)
c.900 -950
Manjula (or Munjala)
Prakashpattana
Laghu-manasa (932)
c. 1000-1050
Shripati*
Dhi-kotida-karana ( 1039)
c. 1050-1 110
Brabmadeva
Mathura
Karana-prakasha ( 1092)
c.1060-1110
Shaiananda
Puri,Orissa
Bhasvati-karana (1099)
b.1114
BhaskaralT
Vijjalavida, Bijapur
Karana-kutuhala (1183)
c. 1280 1350
Chakreshvara
Mahadeva
Rasina, Godavari
Mahadevi (1316)
13- 14th cent.
Vararuebi
Kerala
Vakya-karana (1282/1306)
1367
Mahadeva
Trymbak, Godavari
Kamadhenu-karana
c. 13601455
Parameshvara
Alattoor, Kerala
Drig-ganita ( 1430)
1375
Ishvara
Karana-kantirava
1417
Damodara
Bhata-tulya
c. 1450- 15 10
Keshava
Nandgaon,
Maharashtra
Graha-kautuka ( 1496)
c. 1475-1550
Chitrabhanu
Karanamrita(1530)
c. 1500-1560
ShankaraVariyar
Kerala
Karana-sara
b.1507
Ganesha Daivajna
Nandgaon,
Maharashtra
Graha-laghava ( 1520)
c. 1540 1600
Dinakara
Kheta-siddhi (1578)
Chandrarki (1578)
c. 1550-1621
AchyiUaPisharti*
Kundapura, Kerala
Karanottama(1593)
c. 1500 -1620
Ramachandra Bhata
Delhi
Rama- vinoda (1590)
c. 1550 -1620
Vishnu
Golagram, Godavari
Suiyapaksha-sharana-
karana (1608)
c.1589
Dhundhiraja
Parthapura, Godavari
Graha-mani
c. 1590-1650
Nagesha
Gujarat
Graha-prabodha (16 19)
4
Historical perspective
Year Author 1 Place Work
c. 1600-1660
Krishna
Konkana
Karana-kaustubha (1653)
c. 1650- 1720
Jatadhara
Sarhind, Punjab
Phatteshaha-prakasha (1704)
c. 1660-1740
Putumana Somayaji
Shivapura, Kerala
Karana-paddhati
c. 1730-1800
Nandarama Mishra
Kamyaka-vana
Grahana-paddhati (1763)
c. 1740-1800
Shankara
Dvarka, Gujarat
Karana-vaishnava (1760)
c. 1750-1800
Manirama
Graha-ganita-chintamani (17 14)
c.1781
Bhula
Narmada
Brahma-siddhanta-sara
c. 1800-1839
Shankara Varma
Katattanadu, Kerala
Sad-ratna-mala (1823)
c. 1800-1850
Jyotiraj
Nepal
Jyotiraja-karana ( 1832)
1 . Asterisk denotes appearance in Table 1 also.
2. The number in bracket after the work is the year of its composition or the epoch chosen for
computations.
lived right into the present century. Samanta Chandrasekhara Siruha (1835-1904) was bom in a
princely family in the small village ofKhandapara in western Orissa. Introduced to the ancient
Siddhantic literature in the family library, he soon noticed that the predictions did not match
observations. Following instructions in the old texts, he made his own instruments. His main
instrument was a tangent-staff, made out of two wooden rods joined together in the shape of a
T. ' The shorter rod was notched and pierced with holes at distances equal to the tangents of angles
formed at the free extremity of the other rod '. Calling it Mana-y antra (measuring instrument)
he used it with a precision which was more due to his innate abilities rather than the instrument's.
Using Bhaskara n as his role model he then set out in 1894 to write on palm leaf his Siddhanta-
darpana , consisting of 2284 shlokas of his own composition to which were added another 216
called from old Siddhantas, especially Bhaskara ITs Siddhanta-shiromani and Surya-siddhanta.
Throughout the Siddhantic period instruments and observations played second fiddle to
computations. Observational results were not explicitly recorded, the description of astronom-
ical instruments was condensed in a single chapter, Yantra-adhyaya. Although Bhaskara II is
credited with devising a rather versatile instrument, phalaka-y antra , there is no gainsaying the
fact that observational astronomy came to its own only in the medieval times thanks to India's
interaction with central and west Asia.
5
Astronomy in India: A Perspective
Zij astronomy
This phase of post-Siddhantic world astronomy may be called Zij astronomy , because the
main occupation of its astronomers was the preparation of Zijes that is astronomical tables. Zijes
fall into three categories: (i) Zij-e-Rashadi (direct tables) based on actual observations; (n) Zij-
e-Hisabi (calculated tables) obtained by correcting observational tables for errors, precession,
etc; and (iii) Zij-e-Tas'hil (simplified tables) which were simplified versions of other tables, for
example, for the moon alone. The Zij period began in the 9th century at Baghdad with the
translation of Brahmagupta's Sanskrit works into Arabic, and essentially came to an end in India,
with the compilation of Zij-e-Muhammad Shahi in 1728 by Raja Jai Singh Sawai. Siddhantic and
Zij astronomies flourished simultaneously.
Zij astronomy made its debut in India under the patronage of King Ferozshah Tughlaq
who ruled at Delhi from 1351 to 1388. Arabic and Persian Zijes were copied and commented upon.
Several books on astronomy were written during his reign, and astrolabes constructed. On his
orders, an astrolabe was placed on the highest tower in his capital Ferozabad (in Delhi). In
addition, Ferozshah also took steps to Sanskritize instrumentation astronomy. On his orders,
Mahendra Suri, head astronomer at the royal court, prepared in 1370 Yantra-raja, a monograph
on astrolabe. This was the first Sanskrit work exclusively devoted to instrumentation, and was
the subject of many later commentaries. Table 3 lists Sanskrit texts exclusively devoted to
astronomical instruments.
From 18th century, we have Raja Jai Singh Sawai's treatise on instruments, Yantra-
prakara, essentially completed before 1724, with some additions made up to 1729. In 1732, his
astronomer Jagannatha translated Nasir al Din al Tusi's (1201-74) Arabic recension of Ptolemy's
Almagestinto Sanskrit under the title Samrata-siddhanta, , To it, he added a supplement describ-
ing various instruments. Jai Singh went on to establish a number of (pre-telescopic) masonry
observatories. The Delhi Observatoiy set up during 1721-24 was followed by a bigger one at his
new capital Jaipur (1728-34). He built smaller ones at Mathura, Ujjain and Varanasi between
1723 and 1734. (All dates are estimates.) The Varanasi Observatoiy was housed in an already
existing building; it is probable that Jai Singh renovated an old observatory. Jai Singh's
instruments and observations have been extensively dealt with in the literature.
Jai Singh's edifice of science did not survive for long. In 1745, two years after Jai Singh's
death. Emperor Muhammad Shah invited Father Andre Strobel to come to Delhi and take charge
of the Observatory. He declined. In 1764 the Observatory was severely vandalized, when Javahar
Singh, son of Suraj Mai, the Jat Raja of Bharatpur, plundered Delhi. More than 150 years later.
6
Historical perspective
Table 3. Instrumentation texts in Sanskrit
Year
Author
(Place)
Woik
Instrument
1370
Mahendra Sun
(Delhi)
Yantraraja
Astrolabe
c.1400
Padmanabha
Y antra-khanavali
Astrolabe Dhruva-bhiamana-yantra
1428
Ramachandra
(Sitapur, U.P.)
Yantra-prakasha
Misc.
15th cent.
Hema (Gujarat)
Kasha-yantra
Cylindrical sundial
b.1507
GaneshaDaivajna
Praloda-yantra
Sudhiranjana-yantra
Cylindrical sundial
Graduated strip
c. 1550-1650
Chakradhara
(Godavari)
Yantra-chintamani
Quadrant
1572
Bhudhara
(Kampilya)
Turiya-yantra-
prakasha
Quadrant
c. 15 80- 1640
Jambusara Vishrama
(Gujarat)
Yantra-shiromani
(1615)
Misc.
fl.1720
Dadabhai Bhatta
Turiya-yantrotpatti
Based on Chakradhara’ s work
1688-1743
Jai Singh
Sawai (Jaipur)
Yantra-prakara
Yantra-rajarachana
Misc.
Astrolabe
c. 1690- 1750
c. 1700-1760
Jagannatha
(Jaipur)
Lakshmipati
Samrala-siddhanta
(1732)
Dhruva-bhramara-
yantra
Samrata-yantra
Tr. of Almagest with
suppl. on instruments
c.1700-
Nayansukha
Upadhyaya
Yantra-raja-
risala-bisa-
baba or Yantra-raja-
vichara-vunshadhyay
Astrolabe (Tr. of MS by
Nasir alDinalTusi,
13th cent., Iran)
c. 1750-18 10
Nandarama Mishra
(Kamyakavana,
Rajasthan)
Yantra-sara(1772)
Misc.
c. 1750-18 10
Mathuranatha Shukla
(Varanasi)
Y antra-raja-ghatana
(1782)
Astrolabe
c. 1736-18 11
Chintamani Dikshit
Golananda(1800)
Misc.
7
Astronomy in India: A Perspective
1. A page from the Sanskrit manuscript Yantra-raja-kalpa (1782) by Mathuranatha, describing the construction
of an astrolabe. The manuscript, copied in 1820, is at Sampumanand Sanskrit University, Varanasi (S.R.Sarma).
2. Raja Jai Singh Sawai’s Observatoiy, Jantar Mantar, Delhi, photographed in 1911 a year after its renovation
(Journal of Astronomical Society of India, Calcutta, vol.2, 1912).
8
Historical perspective
the then Maharaja of Jaipur perfunctorily renovated the Observatory to give it a presentable look at
the time of the 1911 Delhi darbar of King George V. (The Delhi and Jaipur Observatories are
now in a rather dilapidated state and no more than popular tourist spots.
Perhaps the most telling commentary on Jai Singh's dedicated but largely irrelevant
scientific enterprise comes from the rather disconcerting fact that his grandson converted Jaipur
Observatory into a gun factory and used his ancestral 400 kg astrolabe for target practice.
Advent of modern astronomy
Modem astronomy came to India in tow with the Europeans. The earliest recorded use
of telescope in India was rather atypical; it was in the field of pure astronomy rather than applied.
The observer was an Englishman, Jeremiah Shakerley (1626-c. 1655). He was one of the earliest
followers of Kepler and viewed the 165 1 transit of Mercury from Surat in west India. He could
however time neither the ingress nor the egress. His observation therefore was of no scientific
use and remains a curiosity. More representative of the things to come was the work of the Jesuit
priest Father Jean Richaud (1633-93) who in 1689 discovered from Pondicherry that the bright
star Alpha Centauri is in fact double.
Early use of telescopic astronomy by the Europeans as a geographical aid in India was
desultory, sporadic and often motivated by personal curiosity. The 1761 and 1769 transits of
V enus were perceived as a continuation of the ongoing rivalry between France and England, and
brought many instruments and a general awareness of astronomy to colonial India. What however
led to the institutionalization of modem astronomy in India was not the love of stars, but rather
the fear of the Coromandel coast. Rocky and full of shoals, and devastated by two monsoons a
year, India's east coast became the graveyard of many a sailing ship. Its survey literally became
a matter of life and death for the British. Accordingly, a well-equipped, trained surveyor -
astronomer Michael Topping (1747-96) was brought to Madras in 1785.
Madras Observatory (1786)
Next year, perhaps more by design than chance, there came up at Egmore in Madras a
small private observatoiy. Its founder was William Petrie (d. 1816), an enlightened and influential
9
Astronomy in India: A Perspective
company officer, who later officiated as the
governor of Madras for a few months. It was
used by Topping as a reference meridian and on
Petrie's persuasion was taken over by the com-
pany in 1790. Two years later the Observatory
moved to its own campus at Nungambakkam in
Madras, where some of its old remnants can
still be seen. A hundred years later, in 1899,
astronomical activity was shifted to
Kodaikanal, and the Madras Observatory be-
came a purely meteorological observatory.
One of the instruments that Petrie bequeathed
to the Observatory was a pendulum clock by
John Shelton. Believed to be made for the 1769
transit of Venus and identical to the one used by
Captain James Cook in his voyages, it is still
ticking at Kodaikanal, a witness to the advent
and growth of modem astronomy in India.
In the early years Madras Observatory
not only provided the reference meridian for the
work of the Great Trigonometrical Survey of
India (GTS) but also manpower and instru-
ments. Increasing overseas involvement of Brit-
ain required familiarity with the southern skies.
Accordingly, in 1843, after 13 years of pains-
taking work with the newly acquired transit
instrument and mural quadrant (both by Dollond
and with 4 inch aperture telescopes), Thomas
Glanville Taylor (1804-48), former assistant at
Greenwich, produced the celebrated Madras
Catalogue of about 1 1000 southern stars. It was
hailed by the Astronomer Royal Sir George
Biddell Airy as the greatest catalogue of mod-
em times'. (It was revised in 1901.)
3. Gridiron pendulum clock by John Shelton. Iden-
tical to the one used by Captain Cook in his famous
voyages, and to the one used by Charles Mason and
Jeremiah Dixon in N. America to determine the
Mason-Dixon Line, this Shelton was a part of the
original equipment of the Observatory set up by
William Petrie at Madras in 1786. The clock has
been at Kodaikanal since 1899, and is still ticking.
10
Historical perspective
4. Six inch aperture lens telescope on English mounting, by Lerebours & Secretan of Paris. Sketched in colour
by Charles Piazzi Smyth in 1851. (The original is at the Royal Observatory, Edinburgh.) The telescope was ordered
for Madras Observatory. Since modified, it is now at Kodaikanal.
5. Five inch aperture, 7 foot focus, lens telescope on English mounting by Dollond, it was acquired by Trivandrum
Observatory in 1842.
11
Astronomy in India: A Perspective
12
6. A (retouched) sketch of Trivandrum Observatory (Madras Journal of Literature & Science, voJ. 6, 1837).
Historical perspective
7. The title page of a booklet in Urdu brought out by Chintamani Ragoonathachary on the occasion of the 1874
transit of Venus. (His names is spelt variously). He was an assistant at Madras Observatory, and is the discoverer
of a variable star R Reticuli.
13
Astronomy in India: A Perspective
In 1850, the Observatory acquired its first fixed extra-meridional instrument, a 6 inch
aperture lens telescope by Lerebours & Secretan of Paris. It was used by Captain William
Stephan Jacob (1813-62) to show that the recently discovered crepe ring of Saturn was in fact
translucent. (The same diseoveiy was independently made a little later by William Lassel at
Malta using a 20 inch reflector.) The only other telescope at Madras, an 8 inch lens equatorial
by Troughton & Simms, was ordered in 186 1. ( Both these telescopes are now at Kodaikanal.)
The Madras Observatory had already become redundant as far as utilitarian astronomy
was concerned. And when observatories came up in South Africa and Australia, even the British
astronomers lost interest. Norman Robert Pogson's( 1 829-91) 30 years' uninterrupted stint from
1861 till his death is a tragic testimony to the wasted opportunities at Madras. He was the first
astronomer at Madias who did not have any surveying connection. His own neurosis was matched
by the Astronomer Royal's imperiousness. Left to himself Pogson would have liked to extend
Argelander's survey to the southern skies and work on his variable star atlas. Instead, he was
forced to cany on routine, drab, irrelevant observations of transits year after year, which he most
obstinately refused to reduce and publish. No new instruments were ordered during Pogson's long
tenure. What kept the Observatory in working order was the help given by the workshops
established by the government's public works department for its own use.
Watching the GTS and the Madras Observatory at work, two native rulers came forward
to extend patronage to modem astronomy. It is not that they strove to update the elements of
traditional astronomy in the light of new developments in the west or wanted their subjects to
learn new astronomy. Instead, they simply funded British efforts. When the Nawab of Oudh
(correctly Avadh, eastern Uttar Pradesh) decided in 183 1 to set up an observatory he asked the
governor general to send one of his GTS officers (Major James Dowling Herbert 179 1-1833)
as the director. As befit a Nawab's whim, Lucknow Observatory was equipped with the best
instruments money could buy, but closed down as soon as the novelty and the instruments wore
off. The Observatory was abolished in 1849, and ransacked in 1857. In the meantime all the
records of the Observatory, reduced as well as unreduced, were eaten by ants. Thus ended a first
class, though unproductive, observatory which need not have been set up in the first place.
Circumstances attending the Trivandrum Observatory were slightly different. Here the initiative
came from the British men of science, whom the King gladly obliged. The Observatory was
established in 1837 with John Caldecott (1813-47) as the astronomer. Astronomy met the
same fate as at Lucknow. But thanks to Trivandrum's proximity to the magnetic equator and to
Madras presidency, the Observatory could do sustained work in the fields of magnetism and
meteorology under John Allan Broun (1817 - 79), on the lines suggested by the British
Association for the Advancement of Science.
14
Historical perspective
Advent of physical astronomy
While positional astronomy was slugging it out at Madras, there was taking shape in
Europe the new science of physical astronomy or astrophysics. Spectroscopic and photographic
techniques were used in the Indian observations of the solar eclipses of 1868, 1871 and 1872,
which attracted observers from Europe also. The French astrophysicist Pierre Jules Cesar
Janssen (1824-1907) observing .the total solar eclipse of 1868 from Guntur (now in Andhra
Pradesh) detected a spectral line due to a new element, aptly named helium by the independent
co-discoverer Joseph Norman Lockyer (1836-1920). During his post-eclipse stay at Simla,
Janssen created the first spectrohelioscope, which facilitated daily examination of the sun. It
was the transit of Venus of 9 December 1874 that led to institutionalization of astrophysics in
India. This time the state had no major stake in the new astronomy . The initiative and the pressure
came from the European solar physicists who wanted the benefit of India's sunny days for their
research. The government was interested in the work as it was told that a study of the sun would
help predict the failure of monsoons, then as now India's life-line.
Dehra Dun Observatory (1878-1925)
When India-based Col. James Francis Tennant (later Lieut - Gen. and President of the
Royal Astronomical Society) requested the government for setting up a solar physics observatory
with the instruments already in India for the 1874 transit, he was turned down. The government
was however more responsive when Lockyer used his equation with Lord Salisbuiy, the secretary
of state for India. Salisbuiy wrote to the viceroy on 28 September 1877: 'Having considered the
suggestions made by Mr.Locky er, and viewing that a study of the conditions of the sun's disc in
relation to terrestrial phenomenon has become an important part of physical investigation, I have
thought it desirable to assent to the employment for a limited period of a person qualified to obtain
photographs of the sun's disc by the aid of the instrument now in India [for transit of Venus
observation]'. Accordingly, starting from early 1878 solar photographs were regularly taken at
Dehra Dun under the auspices of Survey of India, and sent to England every week. Dehra Dun
continued solar photography till 1925, but more out of a sense of duty than enthusiasm. The larger
of the two photoheliographs fell into disuse, and in 1898 Lockyer was stung by on-the-spot
discovery that 'the dome has been taken possession of by bees'.
St Xavier's College Observatory, Calcutta (1879)
Sunny India caught the attention of astronomers in the continent also. The Italian transit-
of- Venus team led by Professor P.Tacchini of Palermo Observatory stationed itself in Bengal, its
15
Astronomy in India: A Perspective
chief instrument being the spectroscope, an instrument not recognized in the equipment of any
of the English parties'. A co-opted member of the Italian team was the Belgian Jesuit Father Eugene
Lafont (1837- 1908) professor of science at St Xavier's College, Calcutta, who though no researcher
himself was an inspiring educator and science communicator. The College provided education to
sons of Europeans, Anglo-Indians, rajas, zamindars, and Indian men of note. Lafont therefore
'secured great influence among these classes' which he put to good use in the service of science.
Tacchini suggested to Lafont 'the advisability of erecting a Solar Observatoiy in Calcutta, in order
to supplement the Observations made in Europe, by filling up the gaps caused in the series of solar
records by bad weather'. Lafont soon collected a sum of Rs 2 1000 through donations, including Rs
7000 from the Lieut-Govemor of Bengal, 'and in a couple of years the present spacious dome was
constructed and fitted with a splendid 9" Refractor by Steinhill of Munich to which was adapted
a large reversible Spectroscope by Browning'. St Xavier's College Observatory did painstaking if
not veiy striking work, thanks to the customary thoroughness and dedication of the Jesuit men of
science. At about the same time there came up at Poona a research observatoiy for entirely different
reasons.
Takhtasingji Observatory, Poona (1888-1912)
This was the most personalized of all observatories. In spite of its name, it was owned
by the Bombay government and was set up for one man, Kavasji Dadabhai Naegamvala (1857-
1938). Naegamvala was a brilliant student In January 1878, he passed his M. A. examination in
physics and chemistry in first class from Elphinstone College, Bombay, and was awarded the
chancellor's gold medal, the highest honour of the Bombay University. He returned to the College
in 1882 to fill the newly created post of lecturer in experimental physics at a salary of Rs 250
p.m. When the Maharaja of Bhavnagar visited Elphinstone College in October 1882, Naegamvala
represented to him for a donation so that a spectroscopic laboratory could be started at the
college.
The government matched the royal gift of Rs 5000 with an equivalent grant and sent
Naegamvala to England to finalize the equipment 'in consultation with the Committee on Solar
Physics and best makers of spectroscopic apparatus'. While in England Naegamvala boldly
jettisoned laboratory spectroscopy in favour of the celestial. 'Ey advice of the Astronomer
Royal, he allotted the bulk of the funds at his disposal to the purchase of a Reflector Telescope
which would be the largest in India'. (This 20 inch Grubb telescope remained the largest in India
for eight decades, even if half its time was spent in the boxes). In view of the better credentials
of Poona as an astronomical site, the Observatoiy and Naegamvala were transferred in 1888 to
16
Historical perspective
RESISTED No. 0.661
\w»* ; .5
I *'= N , ' . -
THE LATE PROFESSOR KAWASjt DAD AS HOY NAEGAMWALLA,
MA. ERAS., etc.
A renowned and foremost Parses Astro-Physicist, Scientist and Educationist that the community
has produced. He was a well-known research scholar in solar spectroscopic work and an
author in original scientific research work which has found high recognition in
India, Engfand and America.
«H!& S U MlVtft mUSS SlSWlif -tWIPttKU,
*L “ft.
v wwwn mm ^3 Tiia* n$~s hi° 4i*auH<uax r^ntn shus »h
t-J 5N-41 3 * HT/41 ’tfecte GftfeU
sa ' 4 ' ' * jA.rii. ^<15 ir~.ii trrtf
8. Cover page of the April 1 939 issue of the Gujarati-English magazine Hindi Graphic (Bombay) paying tribute to
K.D.Naegamvala: ‘A renowned and foremost Parsee Astrophysicist, Scientist and Educationist that the commu-
nity has produced’.
17
Astronomy in India; A Perspective
the College of Science (now College of Engineering) there. Naegamvala was a member of the
British scientific team that went to Norway in 1896 to observe the total solar eclipse. For the
1898 eclipse that was visible from India, Naegamvala was given a sum of Rs 5000 by the
government to match an equivalent sum raised through donations, ranging from Rs 100 to Rs 500.
(Jamsetji Nusserwanji Tata contributed Rs 250.) The eclipse brought Sir Norman Lockyer and
the Astronomer Royal, Sir W.HAl.Christie, to India who were asked by the Government of India
to report on the observatories here.
The best thing that could have happened to Naegamvala was his discovery by Lockyer.
Lockyer in his report paid glowing tributes to Naegamvala 'who, so far as I know, is the only
person in India practically familiar with solar physics work 7 . On Lockyeris recommendation,
Naegamvala was relieved of teaching duties and appointed full-time director of the Observatory.
He was asked to send data regularly to Lockyer. If Lockyer had had his way, he would have
appointed Naegamvala as the director of the proposed Solar Physics Observatory atKodaikanal
in place of the Madras Astronomer Charles Michie Smith about whose capabilities Lockyer had
a very low opinion. Naegamvala did not go to Kodaikanal, but in 19 12 all his equipment was sent
there, when the Poona Observatory was closed down on his retirement.
Kodaikanal Observatory (1899)
Although the question of upgrading the astronomical facilities at Madras had been brought
up off and on in the British quarters, it was only after the death of Pogson in 1 89 1 that the matter
was taken up in earnest. It was finally decided in 1893 to establish a solar physics observatory
atKodaikanal in the Palani hills of south India with Michie Smith as the director. All astronom-
ical activity was shifted from Madras to Kodaikanal, and the new observatory was transferred
from Madras government to the charge of the imperial government's India Meteorological
Department
To start the Observatory, Greenwich sent (on permanent loan) a photoheliograph, one of
the five identical ones made by John Henry Dallmeyer for the 1874 transit-of- Venus expeditions.
The 6 inch refracting telescope by Lerebours and Secretan of the 1850 vintage was remodelled
and installed for daily photography of the sun. (This must be one of the oldest telescopes still
in scientific use.) The arrival of John Evershed in 1907 (as assistant director to begin with)
heralded the Observatory's golden age. Choosing to come to India, no doubt to work in solitary
splendour, Evershed made Kodaikanal into a world-class, state-of-the art observatory. He put the
newly acquired spectroheliograph into working order, made a prismatic camera using the prisms
18
Historical perspective
he had brought with him, and assembled a number of spectrographs. In 19 1 1 he finally constructed
an auxiliary spectroheliograph and bolted it to the existing instrument so that now the sun could
be photographed not only in the light of calcium K spectral line but also in hydrogen alpha. In
1909, Evershed made the important discovery of radial flow of gases in sunspots (the Evershed
effect). After Evershed's retirement in 1923, the Observatory slowly fell behind times, and
became routine-work oriented. It assiduously took solar pictures every day (weather permitting)
and exchanged them with other observatories the world over, building in the process an enviable
collection of solar pictures that now spans eight complete solar cycles.
Nizamiah Observatory (1901)
The positional astronomy slot that fell vacant in 1 899 with the winding up of the Madras
Observatory was filled by the Nizamiah (Nizam's) Observatoiy at Hyderabad. Its founder was
a rich England-educated nobleman, Nawab Zafar Jung . The Nawab purchased a small telescope
and set up an Observatory at his estate at Phisalbanda in Hyderabad. Very far-sightedly, in
190 1, he took the Nizam's permission to name the Observatoiy the Nizamiah and made sure that
it would be taken over by the government on his own death. He subsequently acquired a 15 inch
aperture Grubb refractor. Curiously, he also obtained an 8 inch aperture astronomical camera,
or astrograph, which later became the Observatory's chief instrument. Zafar Jung died in 1907
and as planned his Observatoiy was taken over by the government. Thus ironically the formal
establishment of the Observatory had to await the founder's death.
The next year the Observatory was formally inducted into an ambitious, on-going,
international programme, called Carte-du-Ciel, or astrographic chart and catalogue. The aim of
this programme was to photographically map the whole sky by assigning various celestial zones
to 18 different observatories around the world. The Nizamiah was asked to take over from
Santiago Observatoiy in Chile, which had defaulted on the (17° to 23° S) zone assigned to it.
Finally the Observatoiy also ended up doing the Potsdam zone 36° to 39° N. In the meantime
(March 1908) Arthur Brunei Chatwood, B.Sc., had been brought from England as the director on
a monthly salary of Rs 1000 (about £ 1200 ay ear). Chatwood's tenure was far from a success. He
did not go beyond the installation of the astrograph at the new site of Begumpet, and quit in 19 14,
unlamented.
Astrographic work could be taken up in earnest only in 1914 with the arrival of Robert
JohnPocock (1889-1918). Pocock was the protege of the influential Oxford professor Herbert
Hall Tumer(186 1-1930) and came 'direct from Oxford', armed with a special grant. The first
usable plate was taken on 9 December 1914, and the first volume ofresults published in 1917.
19
Astronomy in India: A Perspective
When the work finally ended in 1946, a total
of 7,63,542 stars had been observed, and 12
volumes published. These data were in turn
used by the Observatory astronomers to ex-
tract information on proper motion of stars
and on double stars.
Pocock was the last European direc-
tor of the Observatory. On his untimely death
in 1918 he was succeeded by his erstwhile
assistant [Rao Sahib] Theralandoor Pancha-
pageshaBhaskaran ( 1889- 1950), who howev-
er had to wait for fouryears before getting the
formal appointment. Bhaskaran was a foun-
dation fellow of the Indian National Science
Academy (INS A) established in 1935 under
the name National Institute of Sciences of
India (The name was changed in 1970.) In the
Academy records his name appears as T.P.
Bhaskara Sh*stri.
9. The 8 inch Cooke astrograph of the Nizamiah Observa-
tory, used in the Carte-du-Ciel programme 1 9 1 4-46.
Apart from the astrographic work,
Nizamiah had other smaller irons in the fire. The 15 inch Grubb refractor was at long last installed
in 1922 and used for visual observations of variable stars as well as of lunar occultations. The
sun also received some attention, thanks to a Hale spectrohelioscope acquired in 1939. The
Observatory also did some community service. It kept standard time and prepared government
calendars in Urdu and English.
Indian response
Just as the British needed (modem) science in India, they needed Indians also. Accord-
ingly, the 'natives 7 were introduced to English education. As the scientific content of the
administration increased, the natives graduated from being clerks and writers to becoming
doctors and engineers, and finally scientists. In January 1876, Dr Mahendra Lai Sircar, in
collaboration with Fr. Lafont, generated support among Indians as well as in government circles
for setting up at Calcutta the rather oddly named Indian Association for the Cultivation of Science
(IACS). It was the scientific wing of the Indian Association, which was apolitical organization
20
Historical perspective
10. Seven inch aperture lens telescope by Merz-Browning at the Indian Association for the Cultivation of Science,
Calcutta. It was extensively used by C. V. Raman. The Observatory building is to the right (Report of IACS FOR
1913)
of educated Indians and a precursor of the Indian National Congress.Its aim was to enable
the 'Natives of India to cultivate Science in all its departments with a view to its advancement
by original research'. A rich benefactor (Kumar Kanti Chandra Singh Bahadur) presented IACS
with a valuable 7 inch aperture Merz-Browning equatorial telescope in 1 8 80. It however had to
wait for more than 30 years to find a user. Observational astronomy simply failed to take off under
Indian auspices.
Appearance of comet Halley in 1 9 1 0 activated astronomy buffs at Calcutta, who set up
an Astronomical Society of India. There were 192 original members including not only men
of science but also informed laypersons and Christian missionaries. In addition, there were
some rich Indian patrons. The first President was Bengal's accountant general Herbert Gerald
Tomkins (1869-1934), who remained the Society's driving force during its decade-long existence.
It is not clear whether the Society was formally wound up or simply became defunct. The last
available issue of the Society's Journal is dated June 1920. (The name of the Society was reused
53 years later while setting up a new Society at Hyderabad in 1973.)
An active member of the Society was Chandrasekhar Venkata Raman (1888-1970), the
young deputy accountant general and part-time researcher at IACS who quit his lucrative
21
Astronomy in India: A Perspective
government job to take up the newly created Palit professorship of physics at Calcutta Univer-
sity. He served the Society variously as its business secretary, librarian, and director of the
variable star section, and contributed to the Journal as well as to the discussions. He installed
the 7 inch telescope of the IACS and put it to use. Raman maintained a life-long interest in, and
enthusiasm for, astronomy. Another member of the Society was a subjudge, Nagendra Nath Dhar
(1857-1929), who made optics for telescopes at his workshop at Hooghly and discussed his
techniques at the Society meetings.
The most dedicated observer of the time worked outside the pale of the astronomical
society. Bom in a zamindar family at a small village Bagchar in Jessore district (now in
Bangladesh) Radha Gobinda Chandra (1878-1975) left school after failing three times in matricu-
lation examination and took up a job as a poddar (coin tester) at the collectorate at a salary of
Rsl5 monthly. His introduction to astronomy came from a Bengali text and practical acquaint-
ance with the sly from his scientific apprenticeship to a lawyer (Kalinath Mukhegee) who was
editing a star atlas. He observed comet Halley through binoculars and in 19 12 purchased a 3 inch
lens telescope from London for 13 pounds. He became a regular observer of variable stars and
a member of the American Association of Variable Star Observers (AAVSO), which in 1926 gave
him a 6 inch aperture telescope, originally belonging to AA VSO's 'patron and friend Charles
W. Elmer. Chandra certainly made good use of it, communicating a total of 372 15 trained-eye
observations up to 1954, when he finally retired from observing. The value of his prodigious work
lies in the fact that he worked 'at a longitude far from that of most observers, greatly improving
the temporal completeness of the observational records for the stars he observed'. Chandra was
asked to pass on the AAVSO telescope to Manali Kallat Vainu Bappu (1927-82) then at Naini
Tal. The Elmer-Chandra telescope, one of the very few American telescopes in British India (if
not the only one), is now at Kavalur.
A rather atypical scientific enterprise in the 19th century British India was a private
astronomical and meteorological observatory at Daba Gardens. Vizagapatnam (Vishakhapatnam,
now Andhra Pradesh). It was established in 1841 at his residence by a rich zamindar Gode
Venkata Juggarow (18 19-56), who had earlier gone to Madras to take tuition from the astronomer
Thomas Gian vi lie Taylor. On Juggarow's death the zamindari and the Observatory passed on to
his son-in-law Ankitam Venkata Nursing Row (1827-92) who resigned his job as a deputy
collector with the east India company to look after his wife's estate. He furnished the Observatoiy
(in 1874) with a 6 inch Cooke equatorial, a transit circle, and a sidereal clock. He communicated
his observations of solar eclipses, transits of Venus and Mercury, and comets to British astrono-
mers and the Royal Astronomical Society. He obtained equipment for celestial photography but
22
Historical perspective
TIME AND SPACE
THE NEW SCIENTIFIC
THEORY
(Poit “Thk Statbswak.”)
Dr. N. N. Saha, Lecturer on Phyric6
at the Calcutta University, writes as
follows : —
The announcement conveyed *n
yesterday’s Reuter’s cable that Professor
Einstein’s theory of the equivalence
of Time and Space has at last been
verified by observations made during
the. last total solar eclipse w'U be hailed '
with joy by scientific circles all over
the world. If the anouncement be
true, then the time-honoured dogma,
that time and space are quite in-
dependent of each other, will be sub-
verted once for- all.
It is not possible to convey, without •
the use of proper mathematical symbols, |
a very precise concept of the greatness
of the discovery. The theory of .
relativity was first formulated by the-
great Dntcb physicist, H. A. Loren tz,
during the dosing years of the last
century, but was largely recast and
elaborated by Einstein, then a rising!
mathematical physicist of Switzerland, J
and Minkowski, a Russian Jew, whom
11. A clipping from The Statesman , Calcutta, U
November 1919, showing Meghnad Saha's report on
experimental verification of Einstein's theory of
general relativity. Note that Saha’s first initial is
misprinted.
died before he could instal it. He was also the
honorary meteorological reporter to the gov-
ernment of India for Vizagapatam. His son
Raja A. V. Jugga Rao Bahadur (d. 192 1) served
as the Vice-President of Astronomical Soci-
ety of India for a year 1911-12. The Observa-
tory seems to have closed down afterwards.
(The site is now occupied by Dolphin hotel).
In passing, we may notice a small
telescope with an unusual history. In 1938,
the infamous Adolf Hitler presented a 5 inch
aperture Zeiss telescope to the Rana of Nepal.
In 1 96 1, his son, the new Rana, passed on the
telescope to the Everest hero Tenzing Norgay,
who in turn donated it to the Himalayan Moun-
taineering Institute, Darjeeling, which he
headed.
Although the Indian response to obser-
vational astronomy was rather lacklustre,
it was pathbreaking in the field of theoreti-
cal astrophysics. While the well-placed
Calcuttan astronomy enthusiasts were form-
ing their Society, unknown to them a bright
lad in the backwaters of east Bengal was
making his acquaintance with astronomy.
Meghnad Saha (1893- 1955) wrote an essay on
comet Halley in Bengali for the Dacca Col-
lege magazine. As lecturers in physics in the
Calcutta University Saha and Satyendranath
Bose (1894 - 1974) brought out in 1920 an
English translation of Einstein's papers on rel-
ativity. Reviewing it, the science magazine
Nature wrote on 26 August 1922: 'Provided it
is studied with care, the translation will nev-
ertheless be of service to those who are unfa-
23
Astronomy in India: A Perspective
miliar with German, and wish to grapple with the pioneer works on these subjects, some of which
are rather inaccessible 7 . 'Stimulated 7 by Agnes Clarke's popular books on astrophysics, Saha
published in 1920 his epoch-making work on the theory of high-temperature ionization and its
application to stellar atmospheres. Saha's demonstration that the spectra of far-off celestial
objects can be amply understood in terms of laws of nature as we know them on earth transformed
the whole universe into a terrestrial laboratory and laid the foundation of modem astrophysics.
In 1923, Saha moved to Allahabad University as professor of physics where he set up a school
of astrophysics, training outstanding students like Daulat Singh Kothari (1906-93). Saha was the
first one to point out (in 1937) the need to make astronomical observations from outside the earth's
atmosphere. He returned to Calcutta in 1938 as Palit professor. Saha and Bose,like Raman, were
the foundation fellows of INS A. Saha became its President during 1937-38, Bose during 1949-
50, whereas Kothari held the post during 1973-74.
At Madras, Subrahmanyan Chandrasekhar (b. 1910) for the first time applied the theory
of special relativity to the problems of stellar structure and obtained preliminary results on what
after his rigorous work at University of Cambridge came to be known as the Chandrasekhar mass
limit. Chandrasekhar belated by received the physics Nobel prize in 1983.
Curiously, unlike the Indian physicists, pioneering relativists were trained abroad. Nikhil
Ranjan Sen (1894-1963), a class fellow of Saha and Bose, joined as a lecturer in applied
mathematics at Calcutta in 1917. He obtained his D.Sc. in 1921, but went to Berlin where he
obtained his PhD. under the supervision of Prof. Von Laue. Sen’s was the first Indian doctorate
in relativity and he joined INS A as a foundation fellow. Vishnu Vasudeva Narlikar (1908-9 1)
obtained his B.Sc. in 1928 from the Royal Institute of Science, Bombay, and left for Cambridge
University for higher studies, thanks to financial assistance from Bombay University, Kolhapur
state, and the J.N.Tata endowment. He passed the Mathematics Tripos with distinction in 1930
and went on to win the Rayleigh prize for his astronomical researches. Spuming an offer to go
to California Institute of Technology, U.S.A., he accepted an invitation from Pandit Madan
Mohan Malaviya, the Vice-Chancellor of Banaras Hindu University, and came to Banaras as the
head of themathematics department in 1932, where he remained for the next 28 years. He trained
and guided a large number of students including Prahlad Chunilal Vaidya (b.19 18), the author of
the well -known Vaidya metric (1943) forthe gravitational field ofaradiating star. In 1955 came
Amal Kumar Raychaudhuri's (b. 1923) equation that has played a crucial role in investigation on
singularity in relativistic cosmology.
In 1938, BDatt from Sen’s group gave the solution for a gravitationally collapsing
spherical ball of dust This solution was published in 1938 in Zeitschrifi filer Physik, volume
24
Historical perspective
108, page 3 14. It precedes the more commonly known solution of Oppenheimer and Snyder. In
1947, SJDatta Majumdar (University of Calcutta) published a class of exact solutions of Ein-
stein’s equations for the case of an electrostatic field with or without spherical symmetry; these
are now known as the Datta Majumdar-Papapetrou solutions.
By the time the second world war came to an end it was clear that the British rule in India
would soon be over. Plans were therefore afoot to set the scientific agenda for the future. It
is not very well known that during 1943-45 Indian government made sincere efforts to
bring Subramanyan Chandrasekhar from Chicago to KodaikanaL.He was offered a salary three
times the usual. Chandrasekhar however was 'unwilling to be placed in charge of the routine work
of any observatory' and 'would prefer to have a job in University'. Although Meghnad Saha felt
that T)r. Chandrasekhar ought to return to India to train our own boys', this was not to be. Daulat
Singh Kothari was then sounded, but he 'expressed preference to continue as the Head of
Department of Physics in Delhi University'.
Twenty years previously, the British Director General of Observatories had offered to
Saha the number two position under Evershed at Kodaikanal. Now, in December 1945, Saha led
a five-member Committee including the Indian Director-General of Observatories to Kodaikanal
to prepare a plan for 'Astronomical and astrophysical observatories in India'. The Saha Com-
mittee proposed updating of astronomical facilities including, as a part of a long-range plan, 'the
establishment in Northern India of an astronomical observatoiy provided with a large sized
telescope for special stellar work 7 . The Saha report came in handy 20 years later when Bappu
successfully pleaded for a stellar spectroscopic observatory at Kavalur in Jawadi Hills, Tamil
Nadu. (The Observatoiy has since been named after Bappu.) As a follow-up of Saha's report, and
on his own initiative, in 1955 a National Almanac Unit ( renamed Positional Astronomy Centre
in 1979) was set up at Calcutta with a view to helping the traditional almanac makers update
their astronomical elements.
The year 1945 also saw the establishment of Tata Institute of Fundamental Research at
Bombay. Its founder was Homi Jahangir Bhabha (1909-66), a brilliant physicist who shared
Jawaharlal Nehru's vision of a scientific India as well as his aristocratic background. Addition-
ally, he was related to the wealthy and enlightened industrial family of the Tatas. (Sir Dorab
Tata was married to Bhabha's paternal aunt Meharbai in 1898). An important item on Tata
Institute's agenda was 'experimental research on cosmic rays', in which Bhabha was personally
interested. The scientific ballooning in course of time led to the advent of space astronomies
in India. It was also with Bhabha's support that radio astronomy was successfully introduced in
the 1960s by GovindSwarup (b. 1929).
25
Historical perspective
Critique
We can single out three cosmic events from the past two centuries and use them as
benchmarks in discussing the advent and growth of modem astronomy in India. The 1769 transit
of V enus took place at a time when England and France were engaged in bitter rivalry over India.
This brought positional astronomy to India as a navigational and geographical aid. The 1874
transit of V enus saw India firmly in the British grip. The new science of physical astronomy was
taking shape, and the British scientific activity was commensurate with its economic and
political status. Solar physics came to India because the British astronomers wanted data from
sunny India, and because the government was given to understand that a study of the sun would
help predict the failure of monsoons. Interestingly, the work plan prepared by the Royal Society
for Kodaikanal Observatory in 1 90 1 makes no mention of the solar-terrestrial connection. By the
time comet Halley appeared in 1 9 1 0, India's new middle class had become politically assertive
and scientifically ambitious. While the Indians on their own remained mere dabblers in obser-
vational astronomy, they made original contribution in the fields of theoretical astrophysics and
relativity, in which they no doubt felt more at home.
At the time of independence in 1947, India could boast of only two, rather outdated,
observatories: central government's Solar Physics Observatory at Kodaikanal which stood where
Evershed had brought it in 19 1 1, and Osmania University's non- teaching Nizamiah Observaotiy
with equipment of still earlier vintage. Saha Committee's rather pious recommendation for
upgradation of the astronomical facilities was on record, but there was nobody at hand to drive
home the advantage. Bhabha's nascent Institute was still housed in his aunt's mansion, but was
poised for take off in a big way. And finally there were a number of universities which would
multiply but fail to keep the early promise.
27
2
Astronomical facilities
1 radition in optical astronomy, described in the previous chapter, continues. In addition,
facilities have been created in radio astronomy, space astronomy, etc, and a new inter-university
centre has been set up. In a rapidly advancing field that is astronomy new facilities are also being
planned. This chapter provides a survey of the existing and planned astronomical facilities in
the country.
Optical astronomy
During the last 40 years, the old observatories at Kodaikanal and Hyderabad have been
modernized to an extent. At the same time new observatories and research institutes have
appeared cm the astronomical map. Kavalur, Naini Tal, Japal-Rangapur, Gurushikhar, and Udaipur
cover night-time and day-time astronomy.
Vainu Bappu Observatory, Kavalur
i; (Indian institute of Astrophysics)
« i
Kavalur Observatory (long. 78°49' 54" E, lat 12°34' 32.2" N, alt. 725m) located amidst
sandalwood forests in Jawadi Hills in the North Arcot district of Tamil Nadu, was set up in 1968
as a part of the Kodaikanal Observatory. On 1 April 1 97 1, the Kodaikanal Observatory was made
into the Indian Institute of Astrophysics. (Its headquarters are at Bangalore.) On 6 January 1986,
the Kavalur Observatory, as well as its 2.3m telescope, was named after the founder, M.K. Vainu
Bappu.
FACEJITES
There are four major telescopes at Kavalur: (i) 2.3m aperture Vainu Bappu Telescope
(VBT), (ii) 1m Carl Zeiss telescope, the Observatory's workhorse since 1972, (iii) a 75cm
telescope, and (iv) a 45cm Schmidt telescope. There are in addition a number of smaller
telescopes, including a 34cm telescope installed on an old mounting.
28
Astronomical facilities
The VBT has two foci: an f/3.25 prime focus, and an f/13 Cassegrain focus. The original
plan for an f/30 coude focus has been abandoned; it is now proposed to link it through an optical
fibre to the prime focus. The prime focus (scale: 27 arcsec mm" 1 ) is used with a Wynne corrector
system which provides a wide field of 20 arcmin diameter. This arrangement is used essentially
in imaging mode in various filters with a liquid nitrogen-cooled CCD camera system. The present
set up is based on the astronomical system containing a GEC chip of 385 x 576 pixels and operated
through a PC based data acquisition system. All operations of object acquisition and monitoring
as well as data acquisition are remote controlled.
At the Cassegrain focus the main instrument in operation is a Boiler and Chivens
spectrograph with a 15cm camera and the Astromed CCD system as the detector unit. The
13. The dome housing the lm telescope at Kavalur. An identical telescope is at Naini Tal.
29
Astronomy in India: A Perspective
combination of various gratings currently available give resolutions (two pixels) ranging from
2.7 A to 10.8 A. Recently this spectrograph placed on the observing floor (i .e. decoupled from the
telescope) has been linked with the prime focus by a 20m long optical fibre. The other instruments
which are extensively used at Cassegrain focus are an automated polarimeter (developed by
Physical Research Laboratory) and a two-star photometer (built by Indian Space Research
Organization) which is optimized especially for high-speed photometric observations in various
filters. Several other instruments are also used with VBT by visiting observers: e.g., an infrared
photometer and a Fabiy-Perot spectrometer.
The lm Carl Zeiss telescope is of Ritchey-Chretien type normally operated at Cassegrain
focus with an f/13 beam (scale: 16 arcsec mm" 1 ). There is provision to have f/6 and f/2 beams
also. In addition an f/30 eoude focus is also available. The major auxiliary instruments currently
available at the lm telescope are the following.
A direct imaging camera with plate holders of different sizes and with a provision to place
filters is available (though not in regular use). Currently the imaging mode is operated with a
Photometries CCD system which contains a 576 x 384 pixel Thomson chip and a dedicated
computer system for data acquisition. Imaging in various narrow and wide bands is done
regularly. Low and medium resolution spectroscopy is done with a Zeiss Universal Astronomical
Grating Spectrograph adapted with a 25cm camera. The CCD system described above gives a
resolution ranging from 1 1 .4 A to 2.5A. The other regular instruments in use at Cassegrain focus
are a UBVRI polarimeter for linear polarization studies; a single-channel UBVRI photoelectric
photometer; and a PC-controlled single-channel spectrum scanner for broadband work. The data
in these systems are acquired in digital mode through a PC. The f/30 coude focus feeds two high
resolution spectrographs. The most extensively used is the echelle spectrograph (using a 76 lines
mm" 1 R2 echelle with a 150 lines mm" 1 cross dispersion grating) coupled with a 25cm camera.
It gives a resolution of 0.4A. The detector system is the Photometries CCD system. The other
higher dispersion spectrograph has a 400 lines mm" 1 grating and a 120-inch camera yielding a
dispersion of 2.8A mm' 1 in the blue.
The 75cm telescope is also operated at the f/1 3 Cassegrain focus. A UBVRI photometer
coupled to a PC-based data acquisition system is the regular instrument in use. An InSb infrared
JHKL photometer is also being modified for use at this telescope. The 45cm Schmidt telescope
started functioning in 1985. The plate scale is about 150 arcsec mm' 1 . A field of 3° x 4° can be
obtained. The 34cm reflector is provided with a 1P2 1 photomultiplier and is used extensively
for B V photometiy of variable stars.
30
Astronomical facilities
At VBO the other facilities include a VAX 11/780 (VMS) computer system where
'Starlink' and 'Respect 7 software packages are in regular use for data reduction and image
processing. Soon there would be a workstation to enhance the data reduction capability. The
infrastructural support includes a mechanical workshop and an electronics laboratory to service,
maintain and in some cases fabricate the auxiliary instruments and telescopes. There are also
two aluminizing chambers to regularly aluminize the telescope mirrors up to a size of 2.5m.
FUTURE PLANS
Very shortly VBO would be commissioning a new CCD camera with a 1024 x 1024 pixel
chip which can provide a wider field for imaging. An elaborate object acquisition and guiding
unit is under fabrication for the Cassegrain focus of VBT. One of the important instruments being
planned is a fibre-linked coude echelle spectrograph which will provide a spectral resolution of
about 50,000.
Nizamiah and Japal-Rangapur Observatories
and Department of Astronomy
(Osmania University, Hyderabad)
Nizamiah Observatory was nominally setup in 1901 as a private observatory. It was taken
over by the Hyderabad government in 1 908, and attached to the Osmania University in 1 9 1 9. Plans
for the modernization of the Observatory were initiated by the University Grants Commission
in 1954, with most of the funds coming from the U.S . Government through the India Wheat Loan
Educational Exchange Programme. The Department of Astronomy was set up in 1959, and
received special grant during 1964-79. An order was placed in 1957 with Messers J.W.Fecker of
Pittsburgh for the supply of a 48 inch (1.2m) reflector. The telescope parts were received in
December 1964, and the telescope was finally commissioned in December 1968 at the new site
(long. 76° 13' 39" E, lat. 17° 05' 54" N, alt. 695m) named Japal-Rangapur after the two neigh-
bouring villages. In 1983 the historic Begumpet site was vacated and Nizamiah Observatory
shifted to a new building in the Osmania University campus.
FACILITIES
The 1.2m Fecker reflector is provided, at its f/3.5 prime focus, with a Baker corrector
system giving a wide field of 3° x 3°. The following instruments are available at the f/13.7
Nasmyth focus:
31
Astronomy in India: A Perspective
• a dual channel photoelectric photometer with direct current and photon counting
systems
• a Meinel spectrograph with plane gratings giving dispersions of 132, 66, and 33 A
mm" 1 in blue
• a scanning spectrometer with micro-processor based system control and data
logging, with provision for recording the signal in 2000 channels in direct mode
• a 5 12 x 5 12 element CCD imaging system
The f/13, 38cm, Grubb refractor (at the Osmania University campus) is provided with
• a photoelectric photometer equipped with a GR amplifier and a Honeywell strip
chart recorder
• a filar micrometer for measurement of visual binaries.
The 20cm, f/ 15, astrograph has a photographic plate holder for 1 6cm x 16cm plates. It also
has an attached 10 inch refractor guiding telescope with provision for X, Y motion of the eyepiece
for off-set guiding.
The solar radio telescope system consists of the following :
• a 3m parabolic dish antenna with dual polarized horn feed
• an x-band signal generator
• a radiometer receiver
• a time-sharing polarimeter
• a two-channel and a four-channel recorder
• a 16 element Yagi T-airay for metre-wavelength solar studies.
In addition the Observatories have two Gaertner spectroscopic and one photographic
plate-measuring machines, and a Carl Zeiss micro-densitometer with analogue recording. The
computer faciliiy consists of a DCM Spectrum-3 microcomputer with 64K byte memory and a
number of personal computers.
FUTURE PLANS
The mechanical and electrical drive system of the 1.2m telescope will be modernized
to make the telescope more effective. A high - dispersion Echelle spectrograph with blue and
red image tubes is under construction. The image tubes will later be replaced by CCDs.
A 1024 x 1024 element CCD and a Sun work station are being acquired.
32
Astronomical facilities
£j| Uttar Pradesh State Observatory, Naini Tal
The first observatojy to be set up in India after independence, it was started in April 1954
at the old city of V aranasi by the Uttar Pradesh government on the initiative of a cabinet minister
and future chief minister. Dr Sampumanand, himself a Sanskrit scholar with interest in all
aspects of astronomy. The Observatory was placed under the honorary directorship of Avadesh
Narayan Singh, at the time principal of Dev Singh Bisht Government Degree College, Naini
Tal. In November 1955, the Observatoiy, with M.K.Vainu Bappu as the Chief Astronomer (as the
Director was then called), was moved to Naini Tal town. In 1961, the Observatoiy shifted to
its present site on Manora Peak: (long. 79° 27 24" E, lat 29° 2 1' 36" N, alt 1950m), in Naini Tal.
FACILITIES
To begin with, the Observatory was rather modestly equipped; it had a gravity-driven
25cm refractor by Cooke anda 13cm transit instrument Over the years, it acquired progressively
bigger telescopes: a 38cm reflector by J.WJFecker (1959); a 56cm reflector by Cox Hargreaves
& Thomson (1968); and finally a lm Zeiss reflector (1972) that has since been formally named
the Sampumanand Telescope. There is, in addition, a 50/79mm, f/1, Schmidt camera on a triaxial
mount, which was used for satellite tracking during 1958-79.
A number of instruments are available for use at the f/13 Cassegrain focus of the lm
reflector :
* a plate-holder with a field of 45 arcmin 2
a spectrograph having dispersion in the range 30-150 A mm' 1
* an f/2 Meinel camera with a field diameter of 37.5 aremin
* a photoelectric photometer
* a CCD camera with a Thomson chip of 576 x 384 elements of 23 micron size
* a grating spectrometer with a red con array of 1024 elements of 25 micron width,
providing dispersion of 0.25nm and 0.2l5mn per element
An infrared photometer for near-infrared studies is under test Also, a 1024 x 1024
Tektronics CCD chip with a pixel size of 24 micron has been acquired. The 56cm reflector is
provided with two objective prisms and a Baker corrector for photography at the Newtonian focus.
There is also a photometer at the folded Cassegrain focus. The 38cm reflector is used in
conjunction with a photometer.
33
Astronomy in India: A Perspective
The facilities available for solar research are as follows, (i) A 9m focus, Czemey-Tumer
type horizontal spectrograph with a dispersive power of 1 .2 A mm 1 in the first order is fed by
a 45cm diameter coelostat through a 25cm, f/66, off-axis skew Cassegrain telescope, (ii) Another
system consisting of a 25cm coelostat and a 15cm, f/15, objective lens produces a 16/24mm solar
image through a Halle H-alpha filter, (iii) Two recently acquired 15cm, f/15, coude refractors
are being used for obtaining filtergrams in H-alpha, Ca II K, and CN filters and for white light
solar photographs.
The computer facilities consist of a Micro Vax II, a Sun-Spare computer, a Vax station,
and a number of personal computers. Reduction packages MIDAS, VISTA, and IRAF are
available. The Observatory has an in-house optical workshop, machine shop, aluminizing lab-
oratory, and electronics workshop.
FUTURE PLANS
Subject to availability of funds, there is a proposal to set up a 50cm vacuum solar optical
telescope with a view to cariying out high spatial and temporal resolution studies of solar flares
and associated active regions. It is planned to obtain filtergram and corresponding magnetogram
data so that solar activity can be understood in an integrated manner.
|2| Gurushikhar Infrared Observatory
| !j (Physical Research Laboratory)
ir 'I
The Gurushikhar Observatory, Mount Abu, in south Rajasthan (long. 72° 46' 47.5" E, lat.
24° 39' 8.8" N, alt. 1680m) is a part of the Physical Research Laboratory, Ahmedabad. Clear nights
at the site average 200-250 a year, with the observing season extending from October to May.
During the dry winter months, precipitable water vapour over Gurushikhar has a typical value
of about 3mm. The Observatory houses a 1.2m reflector with an f/ 13 Cassegrain focus. A high-
resolution Fourier transform spectrometer, an infrared polarimeter, and near-infrared array de-
tector camera are being installed. It is planned to install, in about a year's time, an f/45 vibrating
secondary and coude focus.
The astronomy group at PRL has developed expertise in focal plane instruments for
special studies. These include high-resolution Fabiy -Perot spectrometers, both aperture scanned
and two dimensional imaging versions; a stellar photometer and infrared photometers with 1 ms
time resolution.
34
Astronomical facilities
Kodaikanal Observatory
(Indian Institute of Astrophysics)
Established as a solar physics observatory in 1 899, Kodaikanal Observatory (long. 77° 28'
07" E, lat 10° 13' 50" N, alt. 2343m) is now a field station of the Indian Institute of Astrophysics.
FACILITIES
. (i) A 15cm aperture English-mounted refractor by Lerebours and Secretan of Paris,
acquired in 1850, but remodelled by Sir Howard Grubb in 1898 to serve afc a photoheliograph,
giving 20cm diameter white-light pictures of the sun.
(ii) Twin spectroheliographs, giving 6cm diameter full-disc photographs of the sun in Ca
K and H-alpha light. The arrangement consists of a 46cm diameter Foucault siderostat which
feeds light to a 30cm aperture, f/22, Cooke triplet lens. The two-prism Ca II K spectroheliograph
was acquired in 1904 from Cambridge Scientific Instruments Co., while the grating H-alpha
spectroheliograph was bolted onto the original instrument by Evershed in 19 1 1 .
(iii) A Hale spectrohelioscope for visual observations of the sun, received as a gift from
Mount Wilson Observatoiy in 1933.
14. The dome of the solar tunnel telescope at Kodaikanal. To the left can be seen the spectroheliograph building
with the Bhavnagar dome in the background. To the right is a radio antenna no longer in use.
35
Astronomy in India: A Perspective
(iv) The tunnel telescope by Grubb Parsons, purchased in 1958, consists of a 60cm
diameter two-mirror coelostat (mounted on a 1 lm high tower) that directs light via a flat mirror
to a 38cm aperture, #90, achromat which forms a 34cm diameter solar image at the focal plane.
A littow-type spectrograph and a spectroheliograph capable of giving pictures in a chosen line
are available for use. These remain the country's main facilities for high spatial
(5.5 arcsec mm" 1 ) and spectral resolution (up to 9 A mm” 1 ) solar work.
(v) A PC-based spectropolarimeter for measuring all three components of the solar
magnetic field was built in 1992. This has an asynchronous Peltier-cooled CCD camera for
recording the Zeeman-broadened spectra, a microprocessor-based, stepper motor that rotates the
modulating retarder plate, and a video frame grabber that can digitize and store 16 frames of 512
x 512 pixels at a rate of 170ms per frame.
FUTURE PLANS
It is planned to modernize solar observational facilities. Arrangements are being made
to obtain filtergrams in Ha and CallK, using narrow-band filters and large-format charge coupled
devices. A Zeiss double monochromator is being installed to obtain scatter-free spectra. In the
case of the tunnel telescope, it is planned to improve image stability and guiding, and instal CCD
detectors. Replacement of the old lens and grating would reduce scattered light in the spectrograph.
The spectroheliograph is being provided with a linear reticon detector for improving spectral
resolution. It will also enable acquisition of spectroheliograms in narrow absorption lines.
Udaipur Solar Observatory
Mm (Physical Research Laboratory)
_[n jl
The Udaipur Solar Observatory (long. 73°42' 45" E, lat. 24°35' 08" N, alt. 301m) was set
up in 1975 on a small island in the Fatehsagar lake in Udaipur, under the aegis of the Vedhshala
Trust, Ahmedabad. In December 198 1, the Observatory was taken over by the government of
India's department of space, and attached to the Physical Research Laboratory, Ahmedabad.
FACILITIES
The Observatory began its scientific work with an old 10 foot spar telescope, received
as a gift from CSIRO, Australia. The telescope has been considerably modified. A 25cm aperture
singlet objective lens has been installed on the spar, for taking H-alpha chromospheric pictures
with 35mm film and video camera. In addition, a 15cm aperture telescope has also been mounted
on the spar for taking white light pictures of the solar disc, A Razdow telescope has been acquired
36
Astronomical facilities
from the National Oceanic and Atmospheric Administration, U.S.A. for monitoring full-disc
chromospheric activity. A coude 15cm aperture telescope by Zeiss with a Littrow spectrograph
is available for taking multislit spectrograms of flares, prominences, etc. in H-alpha light. A
digital data acquisition system has been acquired. All solar telescopes are equipped with solar
guiders. It is now planned to instal a piezo-electric driven image stabilizer. Efforts are under
way to build a photoelectric scanning spectrograph to obtain spectroheliograms in Helium
10830 A line. Efforts are also being made to build a video magnetograph for measuring longitu-
dinal magnetic and velocity fields, using a lithium niobate solid Fabry -Perot etalon as a narrow-
band (0.13 A passband) filter.
Proposed National Large Optical Telescope
There are at present in the country four lm class telescopes and one 2in class telescope.
A proposal has been put forward to the government of India for a larger telescope. The proposed
4m-class telescope would incorporate the following three features in common with the present-
day large telescopes: (i) a fast and light-weight primary mirror, (ii) an altazimuth mount for
compact mechanical structure, and (iii) active correction of the optics during the observations
for obtaining a sharp image. A well equipped telescope of the proposed type would allow imaging
of objects brighter than about 27mag arcsec' 2 as well as medium-resolution (about 1 A) spectrosco-
py to a limiting magnitude of about 21 in visible band. The Himalayan ranges offer the best
possibility for a suitable site.
Radio astronomy
Radio astronomy made its debut in India in 1 952 when Kodaikanal Observatory built a
100MHz radio telescope with a twin Yagi antenna for monitoring solar noise. Over the years a
number of receivers were built for operation at other frequencies. In 1956, the Observatory
obtained a custom-built 10cm wavelength radio receiver from the Commonwealth Scientific and
Industrial Research Organization (CSIRO), Australia. (The receiver was put to use in 1965.)
These early efforts at Kodaikanal however remained non-cumulative. In 1956 Physical Research
Laboratory (PRL) set up a simple radio telescope to monitor galactic radio noise with a view
to studying the earth's upper atmosphere. In 1964 an ionospheric opacity meter was built for
measuring ionosphere attenuation at 2 1.3MHz. In July 1967 a solar radio spectroscope operating
at 40-240MHz was installed. This instrument fills a gap between the far-eastern and European
stations for a round-the-clock patrol of solar bursts. In 1969 a time-sharing radio photometer
37
Astronomy in India: A Perspective
operating at 35MHz was set up, and the nextyear a Dicke-switched type microwave (2800MHz)
solar radiometer.
Radio astronomy came to its own in 1963 at Tata Institute of Fundamental Research,
Bombay. The first radio telescope under the new auspices was a grating-type radio interferom-
eter, set up at Kaly an near Bombay, for observing the sun at 6 1 0MHz with an angular resolution
of 2.3 arcmin x 5.2 arcmin. The interferometer was assembled from '32 parabolic dishes from
CSIRO of Australia lying unpacked for several years at NPL [National Physical Laboratory],
New Delhi'. It was in use during 1965-68.
Radio-astronomical facilities now exist at Udhagamandalam (Ooty), Bangalore,
Gauribidanur, Thaltej in Ahmedabad, and at the small village of Khodad near Pune.
National Centre for Radio Astrophysics, Pune
(T ata Institute of Fundamental Research)
FACILITIES
Ooty Radio Telescope
The first major radio astronomical facility, the Ooty Radio Telescope (ORT) at
Udhagamandalam in Nilgiri Hills, Tamil Nadu, became operational in 1970. It consists of a
parabolic cylinder 530m long and 30m wide. The reflecting surface is made of 1 100 thin stainless
steel wires running parallel to each other for the entire length of the cylinder. The surface is
supported by 24 parabolic frames 23m apart. The telescope is installed on a hill which has a
natural slope of about 1 1°, close to Ooty's geographical latitude. The long axis of the telescope
has been aligned in the north-south direction so that the long rotation axis of the telescope is
parallel to the earth's rotation axis. The arrangement makes it possible to track celestial radio
sources for about 9.5 hours eveiy day by a mechanical rotation of the parabolic frames in the east-
west direction. In the north-south direction the beam can be steered by introducing appropriate
phase shifts between the 1056 dipoles along the focal line of the parabolic reflector. At the
operational frequency of 326.5MHz, the half-power beam width is about 2° in the east-west and
about 5.6 arcmin in the north-west. The sensitivity of the Ooty telescope has recently been
improved by a factor of about four by installing a new feed system. The overall system temper-
ature is about 150K. The effective collecting area of about 8000m 2 is equivalent to a 130m
diameter parabolic dish with an aperture efficiency of about 60% .
38
Astronomical facilities
One of the principal objectives of the telescope has been the determination of the
brightness distribution of a large number of weak and distant extragalactic radio sources, using
lunar occultation technique. In addition, the telescope has been used for studying pulsars,
supernova remnants, interplanetary and interstellar scintillations, and recombination lines.
Protoclusters have been looked for and attempts have been made to detect the deuterium line.
The telescope has also been used in Very Long Baseline Interferometric (VLBI) observations
in conjunction with large radio telescopes in Europe including Russia. With improved sensitivity,
the telescope is now being extensively used to search for new pulsars. Another major programme
currently under way is the mapping of the disturbances in the solar wind by monitoring the
interplanetary scintillation of a large number of radio sources round the year. There is also a plan
to undertake a survey of the plane of our galaxy by observing recombination lines at 327MHz.
Ooty Synthesis Radio Telescope
An aperture synthesis telescope at Ooty was set up in the early eighties using ORT as
the main element and by installing seven small low-cost parabolic cylinders of size 22m x 9m
at distances of up to 4km from ORT. In order to achieve a wide field of view, ORT was itself
divided into five sections and the signals received from the 12 antenna elements were mutually
combined to form a total of 66 interferometer pairs. The resulting image had a resolution of about
1 arcmin at 327MHz. The synthesis array was used for studying many galactic and extragalactic
radio sources. Its operation has since been discontinued in view of the much more powerful Giant
Metre- wave Radio Telescope being built.
15. The 530m-long Ooty Radio Telescope.
39
Astronomy in India: A Perspective
Giant Metre-wave Radio Telescope
The Giant Metre- wave Radio Telescope (GMRT) now under construction near Khodad
(site long. 74° 03' E, lat. 19° 06' N, alt 650m), about 80km north of Pune, will be the world's largest
aperture synthesis radio telescope at metre wavelengths. Expected to be fully operational by 1995
end, it consists of 30 fully steerable parabolic dishes of 45m diameter each. Fourteen of the dishes
are being located in a compact central array in a 1 km x 1 km area. The remaining 16 will be
placed along the three arms of an approximately Y-shaped configuration spread over a 25km 2
region. The telescope will operate in six frequency bands, around 50, 153, 233, 327, 610, and
1420MHz, with angular resolution ranging from about 60 arcsec at the lowest frequencies to about
2 arcsec at the highest The metre-wave part of the radio spectrum has remained largely
unexplored, in part due to large-scale man-made interference at these wavelengths in the west.
Fortunately for astronomers, radio interference is not a serious problem in India at present.
A novel cost-cutting, feature of the design is the low-solidity concept of Stretched Mesh
Attached to Rope Trusses (SMART), specially suited for non-Himalayan India where there is
no snowfall. GMRT will have over three times the collecting area of the V eiy Large Array (VLA)
in New Mexico, U.S.A., currently the most powerful aperture synthesis telescope. At 327MHz,
GMRTs sensitivity will be about eight times higher than that of the VLA because of the larger
collecting area, higher antenna efficiency, and a substantially wider usable bandwidth because
of the low level of man-made radio noise in India.
Although the telescope would be truly versatile, an important objective is to search for
the highly red-shifted line of neutral hydrogen emanating from protogalaxies or protoclusters,
with a view to determining the epoch of galaxy formation. (The hydrogen line from clouds
between a red shift of three and ten should be observable at frequencies between about 350 and
130MHz). In addition, GMRT will especially endeavour to search for short-period, especially
millisecond, pulsars, and hopes to be able to bring about a three to four fold increase in the total
number of known pulsars in the Galaxy.
Raman Research Institute, Bangalore
The Raman Research Institute founded by C.V .Raman in the late 1940s was reorganized,
after his death in 1970, as a national institute for research in basic science. It is being funded
by the government of India's department of science and technology since 1972. The main areas
of research are radio astronomy, theoretical astrophysics, general relativity and gravitation, and
liquid crystals.
40
Cl . Bhaskara II’s daughter Lilavali (after whom (he book is named) and her fiance are trying to determine a chosen moment of time by observing
the slow sinking of a small vessel (ghatika) in a tray full of water. According to the legend, unknown to any body, a pearl from Lilavati’s jewellery
blocked the hole in the ghatika making the observers lose track of time. The book Lilavali was translated by Abul Fazal Faizi in AD 1587 on Ak bar's
orders. This Lahore style painting accompanies a copy made by Pandit Dayaram in AD 1857 (Salar Jung Museum, Hyderabad).
o
v>
>>
o
d.
oe
b e
3 3
53 <— <
£ -s
S 2
£ £
1 ■&
S 3
5 2
y 60
.2 -c
y csO
=3 f
a; ©
= -C
P OQ
«C C
C o
E “
_3 .5
■§ -2
c J3
8.3
tt >
It
w ca
^ £
-« 60
M 'C,
5 b
w a
c J=
£
.2 S
60 “5
4 >
^3 «
O §
O va
JIa
5 "!
u w >3
C3. The 2.3m Vainu Bappu Telescope at Vainu Bappu Observatory , Kavalur.
C4. The 1.2m Fecker telescope at Japal-Rangapur Observatory.
C5. CCD camera mounted at the Cassegrain focus of the lm telescope at Uttar Pradesh State Observatory, Naini Tal.
C6. Right: Gurushikhar Infrared Observatory : View of the main building and the smaller dome from the rear. Left: Udaipur Solar Observatory.
C8. The ‘central square’ of the Giant Metre-wave Radio Telescope at Khodad containing 14 of the 30 parabolic dishi
CIO. Huge plastic balloons with parachute and scientific payload, ready for launch.
Cl I. Indian remote sensing satellite, IRS-P2, that was launched by PSLV-D2 on 24 October 1994.
Astronomical facilities
FACILITIES
Decametre-wave Radio Telescope
The Institute has set up a decametre-wave radio telescope at Gauribidanur, near
Bangalore, jointly with the Indian Institute of Astrophysies.This array consists of 1000 dipoles
arranged in the form of letter T.The east- west arm is 1 .4 km long and contains 640 dipoles,
whereas the north-south arm, with 360 dipoles, is 0.45 km long. At the operating frequency
of 34.5MHz this telescope has an angular resolution of 26 arcminx42 arcmin and a collecting
area of 18,000m 2 at zenith. This telescope has been used to study radio emission from the sun,
Jupiter, pulsars and other radio sources of various kinds in our Galaxy and in external galaxies
etc.
Millimetre-wave Telescope
The Institute has set up a millimetre-wave telescope of 10.4m diameter within its
campus. The front-end receiver is a dual-polarization cooled Schottky receiver operating at 20°
K and tunable over a frequency range between 80-1 15GHz. Both beam switching and frequency
switching facilities are available. The spectrometers available include (i) 256 channel filter
bank with 250kHz resolution, (ii) 128 channel filter bank with 50kHz resolution, (iii) 128 channel
filter bank with 1 MHz resolution, and (iv) acousto-optic spectrometers with 40MHz, 120MHz
and 400MHz bandwidths respectively.
Mauritius Radio Telescope
The Institute, in collaboration with the University of Mauritius and the Indian Institute
of Astrophysics, is in the process of setting up an aperture synthesis telescope at Bras D'eau (long.
57°E, lat, 20°N) in north-east Mauritius. It is a ' T ' array with a 2 km long east- west arm and
a 1 km long north-south arm. The east- west arm has 1024 fixed helical antennas with an inter-
element spacing of 2m. The 1 km long north-south arm will be synthesized by observations spread
over 64 days using 32 trolleys on rails with four helices mounted on each trolley. The main
objectives of this telescope will be to (i) map the galactic plane at 150MHz with a sensitivity
of I50mJy and a resolution of 4 arcmin x 4 arcmin at zenith; (ii) produce a catalogue of point
sources in the declination range - 10° to -70° which will be the southern sky survey equivalent
of the 6C sky survey; (iii) study pulsars; (jv) study recombination lines; and (v) study variability
of extragalactic sources.
41
16. An aerial view of the Mauritius Radio Telescope.
17. Interplanetary scintillation telescope at Ahmedabad.
42
Astronomical facilities
Physical Research Laboratory, Ahmedabad
At PRL, which has optical as well as radio astronomical facilities, studies are being
carried out to estimate the density deviation and the scale size of the plasma irregularities in
the interplanetary medium, and to estimate the solar wind velocity by comparing the spatial
fluctuations of the pattern as it drifts across. This will be accomplished by a combination of three
radio telescopes atThaltej in Ahmedabad, Rajkot and Bhavnagar which form a triangle of about
200km baseline. The telescope at Ahmedabad has an aperture of 20,000m 2 and the one at Rajkot
5,000m 2 . The Bhavnagar telescope (5,000m 2 ) is likely to be operational by the year end. The
selection of the sources is being carried out by a set of 32 beams formed in the north-south
direction by a passive device called Buder Matrix.
Space astronomy
India's space programme was launched rather modestly in 1948 when bunches of small
rubber balloons were flown by TIFR from Delhi for cosmic ray studies. Another institute with
interest in cosmic rays was the Physical Research Laboratoiy, Ahmedabad, (PRL) set up by
Vikram Ambalal Sarabhai (1919-71) in November 1947. Over theyears, the TDFR stream has
concentrated on pure astronomical studies from space, while the PRL stream has led to the Indian
space rocket programme.
j) Tata Institute of Fundamental Research, Bombay
During 1948-54, clusters of rubber balloons carrying small payloads were flown to heights
of 25-30km from Madras, Bangalore, Delhi, and Srinagar. Plastic balloons were introduced in
1955. Since 1969 all flights have been launched from MaulaAli, Hyderabad, where an integrated
scientific balloon facility was set up (since renamed TIFR National Balloon Facility). In the
early years, special materials were developed to cope with the characteristics of the troposphere
at equatorial latitudes which is much colder than at higher latitudes. It was but natural that the
expertise gained in the field of scientific ballooning from cosmic ray studies would be enlarged
and applied to the newly opening vistas in astronomy. Since 1956 a total of 419 balloon flights
have been launched. During the last six years, there have been 34 major flights, devoted to X-
ray astronomy, infrared astronomy, and various areas of atmospheric sciences. The balloon
facility has also been used by other national institutions. In addition, it has participated in
international collaborative programmes.
43
Astronomy in India: A Perspective
Following the American discovery of the first extra-solar X-ray source Sco X-l in 1962,
an X-ray telescope was flown on 16 April 1968. In 1973 TIFR began its programme of balloon-
borne far-infrared astronomy, with a simple 30cm telescope, which provided a field of view of
about 8 arcmin. It was followed by a 75cm telescope with a better pointing accuracy and a smaller
field of about 3 arcmin. On its loss at the end ofa flight in 1980, a 100cm telescope was pressed
into service in November 1983. In addition to balloons, rockets have also been used for X-ray
studies (see the following).
FUTURE PLANS
After a few more balloon flights of the 100cm telescope with the two-band photometer,
it is planned to improve the set up in all aspects. The aperture of the telescope will be increased,
and, the orientation capability as well as the photometry improved with a view to studying
individual objects in detail beyond the wavelengths covered by IRAS.
£ Indian Space Research Organization, Bangalore
i
r
1 In 1948, on Bhabha's initiative, an Atomic Energy Commission was setup, followed by
the establishment of the Department of Atomic Energy (DAE) in 1954. In 1962, DAE set up the
Indian National Committee for Space Research (INCOSPAR) with Sarabhai as its chairman. The
next year, an Equatorial Rocket Launching Station was established at Thumba near
Thiruvananthapuram (Trivandrum) and the magnetic equator. India's first, two-stage, sounding
rocketwentup on21 November 1963. (In the 1970s two more launch stations were established
at Shriharikota and Balasore). On Bhabha's death in a plane crash in Januaiy 1966, Sarabhai was
appointed chairman of DAE. Space research activity increased rapidly at Ahmedabad as well
as Thumba. In 1969, Indian Space Research Organization (ISRO) was set up to 'cany on national
programmes of space research and its applications for the social and economic development of
the country 7 . Finally in 1972 there came the establishment of a Space Commission and a full-
fledged Department of Space. (The headquarters are at Bangalore.)
TTiumba's proximity to the magnetic equator makes it especially advantaegeous for
studying cosmic X-ray sources. The first X-ray astronomy payload was launched on 22
Januaiy 1973 using a pin stabilized Centaur II A rocket The payload reached a height
of about 165 km. It was followed by another successful launch on 27 October 1976. Finally
on 24 June 1979, Rohini 560 rocket was used to launch from Shriharikota a bigger and
more sophisticated payload, which reached a height of about 330 km. The programme was
discontinued in the 1980s.
44
Astronomy in India: A Perspective
On 4 May 1994, fourth developmental Augmented Satellite Launch Vehicle, (ASLV-
D4), fired from Shriharikota, successfully placed the Stretched Rohini Satellite Series C2
(SROSS-C2) in a low earth orbit The 113 kg satellite is in an elliptical orbit of 437 km perigee
and 938 km apogee at an inclination of 46 deg. It carries two payloads: a gamma-ray burst
detector; and a retarding potential analyser to measure densities, temperatures and flux
characteristics of ionospheric ions and electrons.
On 15 October 1994 the Polar Satellite Launch Vehicle PSLV-D2, fired from Shriharikota,
placed the 870 kg Indian Remote Sensing Satellite IRS-P2 in a near-polar sun-synchronous orbit
at an altitude of 820 km and inclination 98.6°.
FUTURE PLANS
With the successful launch of PSLV, the ASLV series is being discontinued and a new
Rs.250 crore project undertaken to develop three vehicles of a new series: PSLV -Cl, C2 and C3.
In addition development work is continuing for launching Indian National Satellite (INS AT) for
communication and meteorology.
The Geo-stationary Satellite Launch Vehicle (GSLV) being developed by ISRO will have
the capability to place a 2.4 ton spacecraft into geo-stationaiy transfer orbit It could also be used
to place a smaller, 1 to 1.5 ton, spacecraft into a planetary escape trajectory. Once the launch
technologies are perfected, more attention will be paid to developing payloads including astro-
nomical instrumentation.
Gamma-ray astronomy from ground
Cosmic gamma rays are the most energetic electromagnetic radiation produced by
nature. These rays cannot reach the surface of the earth. A general gamma-ray view of the
universe therefore comes from detectors aboard satellites. Veiy high energy component of this
radiation (energies above 10 12 eV ) can be detected on ground, not directly but through the visible
Cherenkov radiation it produces in the earth's atmosphere. Gamma - ray astronomy in India came
about as a sequel to cosmic ray studies. There are at present, two facilities in this area : one
under Bhabha Atomic Research Centre (BARQ, the other under Tata Institute of Fundamental
Research (ITFR).
46
Astronomical facilities
Nuclear and High - Altitude Research Laboratories
(Bhabha Atomic Research Centre, Bombay)
In 1965, Department of Atomic Energy set up a High Altitude Research Laboratory at
the Himalayan resort of Gulmarg (long. 74° 24' E, lat, 34°03' N, alt. 2743m) for canying out cosmic
ray studies. In 1985, a gamma - ray telescope was set up at Gulmarg. Over the years, research
has been carried out from Gulmarg in a range of other fields also: radio astronomy, solar physics,
atmospheric and ionospheric physics, environmental and botanical sciences, geomagnetism and
aeronomy. In the meantime, in 1973, Nuclear Research Laboratory was established at Srinagar.
A new unit of this laboratory has recently started operations from Bombay and detectors will also
be setup on Gurushikhar.
FACILITIES
The Gulmarg gamma - ray telescope system consists of seven equitorially mounted back
coated parabolic glass mirrors, each of 90 cm aperture and 40 cm focus. The telescope proper
consists of six mirrors arranged in two rows; each row acts as an independent detector bank. Each
mirror in the bank is viewed from its focus by a fast photomultiplier tube through an optical filter
having 90% peak transmission at 4000A and a full width at at half maximum of 500A. The
seventh mirror is used to monitor the night sky for any variation in the atmospheric transparency
conditions during the course of observations.
The telescope was successfully used for detecting short time-scale gamma - ray bursts
from various non-solar galactic sources. The operations however had to be suspended in 1990.
FUTURE PLANS
In 1990 an extensive site survey programme was launched. INSAT-ID satellite cloud
imagery in the infrared and visible bands over the five-year period 1986-91 was analysed.
It turned out that the mean percentage per year of clear nights was highest at Gurushikhar,
Mt Abu (65%) followed by Pachmarhi (52%), Naini Tal (49%), Solan (42%), Jammu (38%),
and Gulmarg (22%). On the basis of this plus other data, it was decided to set up a
Cherenkov type gamma-ray telescope at Gurushikhar, next to the infrared observatory of
the Physical Research Laboratory, Ahmedabad. The plans are as follows.
To start with, two high - sensitivity telescopes, TACTIC and MYSTIQUE are being set
up to observe in the energy range 0.2 Te V to 1 Pe V. TACTIC would comprise altazimuth -
mounted optical reflectors of area 40 m 2 . It would be the first imaging gamma - ray telescope
47
Astronomy in India: A Perspective
19. The imaging unit of the TACTIC gamma-ray telescope under test at the Bhabha Atomic Research Centre,
Bombay.
developed in the country. MYSTIQUE would involve an array of 100 large - area, wide - angle
Cherenkov light detectors, spread over an area 0.4 km 2 .
In addition to studying gamma rays, these experiments can be deployed for other studies:
Charge composition of ultra - high energy cosmic rays ; muon spectrum, which is important from
the point of view of solar neutrino problem ; and search for Te V neutrinos and nuclearites, which
are SUSY dark-matter particle candidates.
48
Astronomical facilities
High Energy Gamma - Ray Observatory, Pachmarhi
(T ata Institute of Fundamental Research)
In 1969, TDFR scientists set up a small gamma - ray telescope at Udhagamandalam. It
consisted of just two 0.9 m diameter parabolic mirrors borrowed from the Indian navy. In 1976,
12 more similar mirrors were added to the array. Further augmentation came a few years later
when there were added eight large, 1 .5m diameter, parabolic mirrors loaned from Smithsonian
Astrophysical Observatoiy, U.S.A. In 1986, the facility was shifted to Pachmarhi (long 78°26
F, lat 22° 28', alt. 1050 m).
FACILITIES
Pachmarhi Atmospheric Cherenkov Telescope now consists of a total of 46 mirrors,
arranged as the banks of steerable, equatorially mounted parabolic mirrors. Of these two banks
consist of seven mirrors, each of 0.85 m diameter. Four banks contain four mirrors, again 0.85
m in diamater. The remaining eight banks consist of two mirrors, 0.9 m and 1 .5 m diamater. For
the last two years the telescope deployed at Pachmarhi has a symmetric array of 12 banks
permitting lateral distribution of Cherenkov light.
FUTURE PLANS
Plans are afoot to fabricate about 200 mirrors of 0.85 m diameter. These mirrors will be
used to form a symmetrical array of 25 individual telescopes each consisting of seven mirrors
on a single steerable mount. This would enable exploitation of a technique already proven at
Pachmarhi and to detect lower and lower energy gamma rays. The array is expected to be ready
in about 18 months time.
University sector
During the British period, universities were the only forum available to the Indians for
carrying out research. Pioneering researchers in theoretical astrophysics and relativity were all
university teachers. In spite of this, astronomy and astrophysics did not become an integral part
of general university education. Many universities no doubt offered astronomy as an optional
course for mathematics students at the graduate level, but this astronomy hardly went beyond
spherical trigonometry. Furthermore, although Nizamiah Observatoiy was attached to the
Osmania University as early as 1919, the arrangement was administrative rather than pedagog-
ical. It is only in the late 1950s that attempts were made to bring modem astronomy to the
universities. Osmania University opened a department of astronomy in 1959. In 1962 Delhi
49
Astronomy in India: A Perspective
University formally renamed its physics department as department of physics and astrophysics
and even offered an M.Sc. degree in astrophysics for a few years. Years later, in 1978, Punjabi
University, Patiala, opened a department of astronomy and space sciences and furnished it with
a 50cm aperture telescope. Osmania and Punjabi remain the only two universities with separate
astronomy departments, but now at least a dozen university departments offer astronomy and
astrophysics as an option to their physics students. Many teachers in physics and mathemetics
departments are engaged in research in astronomical and related sciences.
Indian universities, numbering more than 150, are generally beset with a number of
problems including acute shortage of funds. With a view to upgrading the research and teaching
programmes in the universities, the University Grants Commission of the government of India
decided to set up inter-university centres in specified fields.
Inter - University Centre for Astronomy and Astrophysics,
Pune
Inter-University Centre for Astronomy and Astrophysics (IUCAA) was established in
1 988 at Pune. IUCAA is a research centre in its own right with a small core faculty of researchers
-cum -educators. IUCAA seeks to help the universities in a number of ways. It helps design
of a vigorous academic programme and train teachers for it. With a view to helping the
university and college teachers and research students feel at home with astronomical instru-
ments, IUCAA invites them to participate in specific projects in its laboratories. The IUCAA
instrumentation laboratoiy has begun with a do-it-yourself project of making an automated
telescope. The project involves the users from universities and colleges as active participants
in telescope making.
Helping the teachers in their research programme is an important item on the IUCA A's
agenda. Towards this end it runs an associates' programme, which permits the associates to visit
the Centre for long and short durations so that they can carry out their own work and interact
with other visiting scientists or with the faculty . The Centre also seeks to encourage and help
the university faculty members in carrying out their research at other centres. In this context
it is no coincidence that both IUCAA and the GMRT project are located in the Poona University
campus.Apart from organizing appropriate schools and refresher courses for teachers and stu-
dents, IUCAA also participates in science popularization through interaction with amateur
astronomers, young students and general public.
50
Astronomical facilities
IUCAA boasts of what may soon become the best working library in the country, which
attracts users from all over India. The electronic mail and remote logging on computers in a
worldwide network have broken national barriers to bring the Indian community of astronomers
in close contact with their international counterparts.
FUTURE PLANS
With a core faculty of ten, a comparable number of post-doctoral fellows 45 associates
and a large number of visiting scientists, IUCAA has currently attained about half its optimal
size. It is aspiring to be the main hub of astronomical activity in the country in the university
sector.
To make the associateship programme work, the universities must come to look on
IUCAA as their own field station so that a staff member who has come to use its facilities is
treated as on duty. IUCAA’s overtures to university departments for strengthening astronomy and
astrophysics will need to be reciprocated and taken advantage of.
Experimental gravitation
Experimental studies of gravitation and feebler forces at
Gauribidanur
A high-precision torsion balance has been set up to study the various fundamental
properties of gravitation. The experiment is located at Gauribidanur in a seismologically
quiet arid region near Bangalore, and is jointly run by Tata Institute of Fundamental Research
and Indian Institute of Astrophysics. The aim of the programme is to (i) test the principle of
equivalence of inertial and gravitational masses to an accuracy higher than 10' l4 , and
(ii) to search for hitherto unknown forces weaker then gravity.
The experimental arrangement is as follows. Two half-rings, made of copper and of lead,
each about 8.5cm in radius and weighing 700g, are joined together to make a single ring. A
tungsten fibre, 250cm long and 105 micron in diameter, is used to suspend the ring, keeping its
plane horizontal.The chamber containing the equipment is then evacuated to a pressure below
10“ 8 Torr. To shield the balance from variations of temperature, the whole arrangement is
installed in a specially constructed 25m deep well. Inside the well, four lead masses about 160kg
each are suspended in two columns from the two adjacent arms of a plus-shaped truss, that can
be rotated. These lead masses are counter-balanced by a similar set of brass masses which are
51
Astronomy in India: A Perspective
20. A schematic drawing showing the torsion balance at Gauribidanur. In the centre is the copper-lead ring
surrounded by brass (B) and lead (L) weights.
suspended from diagonally opposite points of the truss.The aim of the experiment is to study the
coupling of any force field generated by these masses with the compositional dipole of the ring,
by measuring its angular deflection using a sensitive autocollimator. In particular, the experi-
ment sought proof, if any, of the existence of a fifth force that couples to the nuclear isospin N-
Z, where N is the number of neutrons and Z of protons. The Gauribidanur experiment became
operational in 1987. The results were essentially negative. Any such force with a range greater
than about lm must have a coupling strength < 5 x 1(T 5 in units of gravity per atomic mass unit
The experimental set up is currently being modified for improved immunity from noise
sources. A new set of experiments is under way to test the principle of equivalence at the level
1 0“ 13 , within the next six months. It is proposed to achieve a sensitivity of 1 O' 14 in the following
three years.
52
3
Research highlights
W hen India entered the second half of the present centiny, it could boast of only two
observatories and astronomical manpower of around twenty. Over the years there has been an
all - round increase in astronomical activity. This chapter describes the current state of research
and gives a brief summary of the important results that have been obtained. Both observational
and theoretical works are described together in broadly classified subject areas.
The sun
The Kodaikanal Observatoiy of the Indian Institute of Astrophysics (HA) and the U daipur
Solar Observatoiy (US O) are exclusively devoted to the studies of the sun. Solar studies form
a major part of activity at Naini Tal and figure in the work of other observatories
The chief highlight of the Kodaikanal Observatoiy's work has been the 1909 discovery
of the Evershed effect, viz., the outward radial flow of gases in sunspots. Later work revealed
that there is a reverse flow at chromospheric heights. Over the years, the Observatoiy has
obtained a long stretch of white-light solar pictures and spectroheliograms. The Ca II K pictures
tell us about the upper chromosphere, Ha pictures about the lower chromosphere, while white-
light pictures provide information about sunspots. The Kodaikanal database has been used to
discover a number of significant correlations among solar phenomena. At the same time, high-
resolution spectra obtained with the tunnel telescope have been analysed to yield important
results.
It has been shown from Kodaikanal that time variation of total plage area on the visible
hemisphere of the sun carries the definite signature of solar rotation. This correlation provides
a convenient method for estimating the rotation of stars which have chromospheres. The solar
chromospheric rotation rate has been found to show variations on the time scales of two, seven,
and 1 1 years. Studies have been initiated to obtain information on solar rotation from precise
53
Astronomy in India: A Perspective
measurements of the old sunspot data. The Ha data for 1905-82 have been used by the HA
scientists to investigate the global properties of large-scale magnetic fields. It has been shown
that the fields migrate towards the poles with a variable velocity of up to 30m s 1 depending on
the phase of the solar cycle. It has been found that there is a correlation between Ca H K emission
and the magnetic field strength in the plages. This correlation can be used for estimating the
magnetic fields of stars from their Ca II K spectra. It has been shown that a day or two prior to
the occurrence of a flare, there occurs a change in the orientation of the Ha filament.
Using fine-quality solar Ca II K spectra, IIA scientists have concluded that the Wilson-
Bappu relationship between K emission line widths and the absolute magnitude of stars mostly
arises due to the elements that make up the quiet atmosphere. This work suggests that the stars
which deviate the most from the Wilson-Bappu relationship are the best candidates for studying
stellar activity cycles! Ca U K line profiles of the sun obtained in integrated light have been found
to vary with the phase of the solar cycle. This indicates that the sun is a variable star. It has been
found that the size of the Ca n K (supergranular) network is a function of the solar cycle : The
cells are smaller at the solar maximum than at the minimum. It has also been shown that within
the bright supergranular boundaries there exist dark regions of 4000-6000 km size. These regions
are characterized by relatively large downflow velocities of 5-8 km s~ l compared to neighbouring
horizontal velocities of about 0.5 km s“ l .
Detailed studies have been carried out at Kodaikanal of velocity and intensity fluctu-
ations in selected solar spectral lines, with special reference to five-minute oscillations. It has
been found that intensity fluctuations are coherent over scale lengths of about 10000 km on solar
surface. The newly built spectropolarimeter has recently been used to obtain a large number of
spectra in quick succession. This facility promises to provide new results in areas such as sunspot
seismology, speckle reconstruction of solar features, and time evolution of solar flares.
USO is a participant in the international programme of Global Oscillation Network
Group (GONG). Udaipur has been selected as one of the six sites distributed around the globe
for making solar velocity oscillation observation for helioseismology. The Observatory has taken
partin a number of international programmes, e.g., solar maximum year, solar maximum mission
satellite. Flare 22/Max 91.
From a large collection of chromospheric observations made from Udaipur, a photograph-
ic atlas of some typical examples of chromospheric activity has been published. The dynamics
and evolution of several solar flares and mass ejections have been studied. From a study of proper
motion of sunspots, it has been possible to estimate the build-up and release of energy in flares.
54
Research highlights
Modelling of magnetic field structure in post -flare loops and flaring arches and study of the
stability of dark Ha filaments on the disc are being carried out.
Patrolling of the sun is done regularly at Uttar Pradesh State Observatory, Naini Tal
(UPSO) to record and analyse flares, surges, prominences and other active features. The rela-
tionship of the morphology of the active features with mass motions and prevalent magnetic
fields is sought. Correlations among the optical, microwave. X-ray emmisions and sudden
ionospheric disturbances have been investigated. The existence of active longitudes on the sun
has been postulated. Relationships between coronal holes, coronal mass ejections and solar flares
have also been studied.
The sun has been studied at decametre radio waves using the Gauribidanur telescope.
Maps have been produced of continuum emmision from the quiet sun and the active regions. The
compound grating interferometer has been used to make high resolution (3 arcmin) one -
dimensional scans of the sun. These scans have in turn been used to measure the varitions in the
east - west diameter of the undisturbed sun, active regions and coronal holes.
Expeditions to observe total solar eclipses have been an important part of work at IIA.
The 1970 total solar eclipse revealed the rather unexpected presence of Ha emission in the
solar corona. Multislit spectroscopy of the solar corona carried out during the successive 1980
and 1983 total solar eclipses has thrown significant light on the physical processes in the corona,
(i) It has been shown that ions have larger random motions in closed coronal loops than in the
open, (ii) At the time of increased solar activity turbulence shows a significant increase, (iii)
The mechanism for excitation of ions in the corona is not uniform, with collisional excitation
dominating near the solar limb and radiative excitation in farther regions. In addition, photomet-
ric and polarization measurements of the coronal structure have often been carried out.
IIA results support the view that there are no large - scale mass motions in the solar
corona. On the other hand coronal interferograms obtained during the 1980 and 1983 eclipses by
scientists from the Physical Research Laboratory, Ahmedabad, (PRL) have been interpreted as
evidence for the existence of large mass motions, especially during the active solar phase. The
passage of the path of totality of the total solar eclipse of 16 February 1980 over Japal-Rangapur
Observatory (JRO) offered a unique opportunity to study the corona, using a large telescope. JRO
astronomers carried out a two-colour polarimetric study of the corona. Besides giving electron
density and temperature in the corona it confirmed the dependence of the brightness of the F
corona on wavelength. Variation of the 3cm radiation from the sun during eclipse was also
studied.
55
22. The sun photographed in the light of the K line of ionized calcium from Maitri station, Antarctica,
9 January 1990.
Research highlights
A three-member team from HA observed the total solar eclipse of 3 November 1994 from
Putre in north Chile. More important from the Indian point of view will be the total solar eclipse
of 24 October 1 995, which will be seen from a stretch of land extending from Iran in the west
to Kampuchea in the east.The path of totality will pass through the states of Rajasthan, Uttar
Pradesh, Bihar and W est Bengal. A number of international scientific teams are expected to visit
north India for the eclipse.
The continent of Antarctica provides a round-the-clock view of the sun. In the local
summer of December 1989-March 1990, a three-member team from DA and UPSO set up a
small observatory at the Maitri station. A combination of a polar heliostat and a 10 cm aperture,
f/30, objective lens was used to obtain pictures of the sun in the light of the Ca II K line.
Uninterrupted data extending over as long as 106 hours have shown that the average life time
of a supergranular cell is about 22 hours. It has been shown for the first time that there is a
correlation between lifetime and size of a cell in the sense that larger cells live longer. Also,
cells associated with remnant magnetic fields live longer than those of comparable size in field-
free regions.
Scientists at the Tata Institute of Fundamental Research, Bombay (TIFR) have taken part
in worldwide efforts to understand the deep interior of the sun. These efforts include trying to
explain the observed low flux of solar neutrinos and modelling the five-minute oscillations of the
solar surface. Theoretical aspects of various solar phenomena are being studied at HA, TIFR,
National Physical Laboratory, New Delhi (NPL) and elsewhere. Theoretical investigations into
the existence of a number of molecular species (diatomic, triatomic and ionic) have been carried
out at UPSO. Molecular constants such as oscillator strengths, dissociation energies, Frank-
Condon factors and partition functions for some molecules have been calculated. Turbulent
velocity for the solar photosphere has been determined using centre-to-limb CH line profile
variations.
Extensive studies at the National Centre for Radio Astrophysics, Pune (NCRA) have
shown that the spectrum of turbulence in the solar wind is best described by a power law with
an 'inner scale' rather than by a Gaussian. This makes it possible to estimate the solar wind
velocity from single-station observations alone. Velocities thus estimated are in close agree-
ment with those derived from the conventional three-station measurements. This powerful
technique is currently being used to study transients in the solar wind and the dependence of solar
wind velocity on heliographic latitude and on the solar cycle.
57
Astronomy in India: A Perspective
Solar system studies
A sky survey using the 45 cm Schmidt telescope was begun at the V ainu Bappu Observ-
atory, Kavalur (VBO) in 1987 for the search of asteroids and other minor bodies in the solar system.
A new asteroid numbered 4130 was discovered on 17 February 1988. This asteroid was later named
Ramanujan after the Indian mathematical genius Srinivasa Ramanujan.
Observations of occultation by solar system bodies have been carried out from VBO for
almost a quarter century now and have yielded important results. Observations made at VBO
contributed to the 1973 discovery of a thin atmosphere on the Jovian satellite Ganymede. Rings
around the planet Uranus were discovered in 1977. Evidence for the suspected existence of an outer
ring around Saturn was obtained in 1984. Mutual occultations of the Jovian satellites have been
regularly observed since 1985. Analysis of these events has yielded improved ephemerides of the
satellites and shown that the tides raised by Jupiter cause deceleration of satellite Io's mean
motion. Mutual events of the Pluto - Charon system and lunar occultation of stars in optical and
infrared for high angular resolution measurements are being regularly observed from VBO. From
balloon-borne observations made by TIFR scientists on 10 December 1980, a reliable value of
97 ±3.5K was obtained for the brightness temperature of Saturn's disc at 76-1 16|um. It was
concluded that the emissivity of the rings decreases substantially at far-infrared wavelengths.
Theoretical work on planetary atmospheres has been carried out at Osmania University,
Hyderabad. Absorption and polarization line profiles were calculated for a semi -infinite plan-
etary atmosphere in the integrated light as well as along the intensity equator and the mirror
meridian for the Raylei gh phase matrix. Comparison with the observation of V enus revealed that
the continuum originates in a deeper layer where Mie scattering predominates, while the lines
arise in a higher layer where Rayleigh scattering prevails. A new definition of the effective depth
of line formation was given which explains the variation of the equivalent width over the disc,
its inverse dependence on line strength and the phase effect in integrated light. H-ftmctions were
calculated for 35 anisotropic phase functions and used for studying the correlation between the
phase function and the phase effect of the equivalent width.
Comets have received considerable attention. Imaging, photometric, spectroscopic,
polarimetric and other observations of a number of comets have been carried out at various
centres. During the occultation of the radio source 2025- 15 by comet Kohoutek in January 1975,
Ooty Radio Telescope was used to observe scintillations through the plasma tail. Halley's comet
was observed in 1985 - 86 by various observatories as part of the International Halley Watch
Programme. PRL scientists observed that comet Austin (1990) was richer in fine particles than
58
Research highlights
comet Halley. Imaging of the nucleus of comet Swift - Tultle (1992) at VBO showed that it had
a rotation period of about 3 days. Multi-fragment crash of comet (1993e) Shoemaker-Levy 9 into
Jupiter was observed during 16-22 July 1994 from Kavalur, Japal-Rangapur and Bangalore at
optical, infrared and radio frequencies. Observing with the 10.4m aperture millimetre-wave
telescope, RRI astronomers recorded that eveiy time a cometary fragment hit Jupiter, its radio
emission at 86GHz went up substantially for a short time. An intense infrared flash in the H-band
caused by the impact of fragment S was detected on 21 July 1994 through the 0.75m aperture
telescope at Kavalur.
Meteoric activity at the Hyderabad latitude has been studied using a 50 MHz continuous-
wave meteor-radar during 1983-92 at the JRO. The group working at PRL came up with valuable
evidence from the analysis of meteoritic data on the early histoiy of the solar system including
a signature of the active early phase of the sun and isotopic records of ambient stellar
nucleosynthesis. Significant results have been obtained on the total electron content of the
ionosphere and the amplitude scintillations of the satellite radio beacon signals recorded at
Hyderabad. Ionospheric irregularities have been studied at JRO by recording the Faraday rotation
angles, using the three-station method, under and the International Atmospheric Programme. An
important result was obtained in 1 969 on the effect of celestial X-ray sources on earth's atmos-
phere while recording field strengths at Ahmedabad of 164 kHz radio waves transmitted from
Tashkent. It was noted that a pronounced minimum recurred night after night during April- July .
This phenomenon was attributed to increased ionization in the lower D-region of the ionosphere
due to the transit of SCO - 1 across 7 1° E, the one-hop reflexion meridian of radio waves from
Tashkent to Ahmedabad.
Stars and the Galaxy
The Milky Way Galaxy and its constituents have been extensively studied from ground
- based observatories.
Classification of Am stars on the basis of their MK spectral morphology has been carried
out using the Meinel spectrograph at the Nasmyth focus of the JRO 1.2m telescope. As many
as 100 spectra of Am stars and MK standards were obtained at 66 A mm" 1 , and their digital
profiles used for classification. Using spectra at a higher dispersion of 33 A mm' 1 , Osmania
astronomers have detected a phase-modulated spectral line variation in some of these Am stars.
A study of chemical composition of classical Cepheids and related chemical
inhomogeneities of the Galactic disc was carried out from VBO. The [Fe/H] index of nearly
two dozen Cepheids was derived. The places of formation of the Cepheids were determined by
59
Astronomy in India: A Perspective
numerically integrating their orbits backwards in time under the influence of the axisymxnetric
and spiral - like gravitational field of the Galaxy. A steeper variation of [Fe/H] accross the
Sagittarius and Perseus arms was encountered as distinct from the overall variation of [Fe/H]
across the disc. Spectroscopic work on Cepheids has continued and chemical abundances in a
number of them have been derived with the help of synthetic spectra.
Photometry and polarimetiy of a number of hydrogen - deficient stars and carbon stars
in UBVRI and JHKL bands have been done at VBO. Several R CrB variables have been followed
in their deep minima and also during the recoveiy phase. Spectroscopy in the visible region has
been combined with extensive IUE data to determine their atmospheric properties, to obtain
information on the circumstellar environments of these stars, and to estimate their chemical
composition.
High dispersion coude spectra of several supergiants of late G and early K spectral
classes have been obtained at VBO. The blue asymmetry of the Ha line profiles in these spectra
was attributed to the occurrence of chromospheric expansion of these stars eventually leading
to mass loss. Detailed radiative transfer models were computed to match the Ha equivalent
widths obtaining in the process the density distribution in the chromosphere as well as the mass
loss rates. The infrared Ca II triplet lines have been surveyed in a large sample of dwarfs,
subgiants, giants and supergiants with the aid of high dispersion coude spectra.. Sensitivity
of the equivalent widths of these lines to gravity, effective temperature and metallicity has been
investigated. These results are of great value in the studies of stellar populations in galaxies.
Observations of SiO masers in red supergiants, in particular the Mira variables, has been
a major programme with the Millimetre- wave Telescope at the Raman Research Institute (RRI).
The study of cometary globules and their kinematics near OB associations (such as the Gum
Nebula, Orion, Cepheus, etc.) is one of the major on-going programmes with this telescope.
Polarimetric studies of individual stars have been carried out at VBO. Of particular
interest have been the post-asymptotic giant branch stars with circumstellar dust shells. The
RV Tauri star AR Pup has been found to show very high linear polarization, ~ 14%, in the U
band. This is the highest polarization observed for a single star not associated with a known
nebulosity. In addition, pre-main sequence stars have been studied polarimetrically . Polariza-
tion maps of young OB associations and molecular clouds have also been obtained from VBO
by HA astronomers.
A detailed spectroscopic study of the Scoropio-Centaurus association was undertaken at
VBO. Rotational velocities of the members of the association down to 8.5 mag were obtained.
The study showed that the stars of the upper Scorpius group were fast rotators as distinct from
60
Research highlights
those of the Centaurus-Lupus and lower Centaurus-Crux subsystems. The faster rotation of the
upper Scropius group was attributed to either accretion effects or to effects of the interaction
with the surrounding interstellar medium that might have partially destroyed the randomness
of orientation. The data on Scorpio-Centaums association were combined with the data on the
other clusters to investigate the effects of rotation on colour indices of stars. A zero-rotation
zero-age main sequence was determined following a conventional cluster fitting procedure. A
possible solution to the blue straggler phenomenon in open clusters in the spectral type domain
of A stars was suggested in which the anomalous position of these stars could be completely
accounted for in terms of their slow rotation.
Star clusters have been studied at VBO, for their intrinsic properties, as testing
laboratories of the theory of stellar evolution and from the point of view of galactic studies to
discern if they showed a spiral pattern. A few of them containing astrophysically interesting
objects like planetary nebulae have been observed in great detail to faint magnitudes. Star
clusters have also been utilised to calibarate and standardize the photometry done at VBO.
An important contribution from VBO has been a detailed photometric study of the
globular cluster Omega Centauri. Photoelectric scans were made along the major and minor axes
in UBVRI. In addition equi density contours were obtained from direct photographs taken with
an f/6 camera in BVI. Using these, the change of ellipticity from the centre to the outer regions
of the cluster was evaluated. A large concentration of blue stars was discovered at a distance
of 2.5 to 5.5 arcmin from the centre. Their distribution was elliptical in contrast to the more
spherical distribution of red stars. Blue bulges were also observed in some other globular clusters.
Using the Fabiy-Perot spectrometer of PRL, IIA astronomers have carried out kinematic
studies of planetary nebulae. Several bipolar nebulae and a few others with peculiar
characterestics have been studied Deep CCD imaging of planetary nebulae in and away from
the emission lines has been done in an attempt to discover the undetected nuclei. Colour excess
maps of many of these nebulae have been prepared using broadband imaging. Particular attention
was paid to M4 - 18, prototype of a class of planetary nebulae with WC 1 1 type central stars.
These observations were combined with IUE and IRAS data to study the properties of the star
and the nebula.
Binary stars have figured prominently on the observers' agenda. The elements of Gamma
Velorum determined from Kodaikanal in 1963 remained the most accurate for almost two
decades. Another star that recieved a good deal of attention in the early days of VBO was
Canopus. High dispersion (2.8 A°mm' 1 ) plates of this star were obtained in the blue region to
studjy the variation of its Ca II K line profile.
Photometric and spectroscopic studies of RS CVn binaries have been persued at VBO
for many years. In addition to accurate period determinations, detailed modelling has been done
61
Astronomy in India: A Perspective
of the spots on a number of these stars (e.g. DM UMa, II Peg, V7 1 1 Tau). Be stars and Be X-
ray binaries have been examined spectroscopically. Rapid variability in the H a line profiles
in a number of them has been closely monitored VBO has participated in the international
MUSICOS campaign on some Herbig Ae/Be stars and the Delta Scuti star 0 2 Tau.
UB V photometry of eclipsing binaries and variable stars has been an ongoing research
project of long standing at Naini Tal. Mass, dimensions, and physical properties have been
determined for a number of eclipsing binary stars. In addition, period studies have been done for
a few of them as well as for Delta Scuti, Beta CMa, and RR Lyr stars. Gravitational radiation
studies of eclipsing binaries are also being carried out.
A number of eclipsing binaries have been observed in UBV passbands by Osmania
University astronomers using their 1.2m telescope at JapaTRangapur. The secondary components
of the Algols have been found to be not only overluminous but also hotter for their mass, indicating
partial loss of their hydrogen envelopes. Improved periods have been obtained for four binaries.
Period changes were studied for 23 systems, several of which were found to be triple systems.
Two new variables have been discovered from JRO. Infrared photometry of Beta Cephei, Delta
Scuti, Be, and RS CVn-type stars was also carried out Optical counterparts of some X-ray
binaries have also been studied in collaboration with X-ray astronomers from TIFR.
The ISRO Satellite Centre (IS AC) has developed photometers for observing the optical
counterparts of X-ray sources. These observations have been carried out in collaboration with
HA. A 14 inch aperture telescope has been installed in the ISRO campus at Bangalore. A two-
channel star and sky photometer has been used to observe chromospherically active stars such
as HR 1099, UX Ari, IL Hya, DM UMa, and DH Leo.
In April 1979 PRL and TIFR scientists working at Kavalur reported detection of infrared
bursts from an X-ray burster. The discoveiy was confirmed six months later by British astrono-
mers at Tenerife. However, no bursts have subsequently been reported from the source.
ISAC has participated in an international campaign called the Whole Earth Telescope
(WET) project in which the same white dwarfs are observed using similar instrumentation from
different longitudes to produce continuous coverage of data for astroseismological studies. The
white dwarf PG 1 159-035 has been shown to have a mass 0.586 times that of the sun, a rotation
period of 1.38d, and a magnetic field of less than 6000 gauss. The twin white dwarf system AM
CVn, earlier observed from Kavalur and Naini Tal, was also observed in March 1990 by the
WET project. Analysis of composite data shows that the 105 Is period decreases at a rate of (3.7
±0.4) 10~ 12 ss~ l . In the case of the single DB white dwarf GD 358, a mass of 0.6 times that of the
sun is deduced. It is also suggested that the white dwarf has a very thin layer of helium.
62
Research highlights
Several classical and recurrent novae have been spectroscopically monitored from VBO
during outburst and a few during quiescence. Spectroscopic differences and similarities between
individual novae in outburst have been studied and the physical parameters of the ejected shell
estimated. Evolution of their photospheric radii and temperature has also been monitored in
a few cases. The results indicate presence of a white dwarf in the recurrent nova RS Oph for
which alternative models exist that do not invoke a white dwarf. The accretion disc spectrum
has been estimated from the observations of novae in quiescence and mass transfer rates and
geometrical parameters of these discs derived. Spectroscopic monitoring of T CrB over a long
base line in time has shown secular as well as orbital phase dependent variation in emission line
strengths. Using the images of the shell of GK Per, the proper motion of individual knots have
been measured and the velocity deceleration derived. Astronomers at PRL have observed dust
formation as early as seven days after eruption in the fast Nova Her 1991. The result is rather
surprising, because fast novae generally do not produce substantial amounts of dust. ISAC
scientists have measured UBV magnitudes of nova Cygni 1992. Polarimetric studies of the
peculiar symbiotic system R Aquarii by PRL scientists have suggested the existence of a
processing jet Line profile studies in Ha give evidence of an expanding shell with a velocity
of about I5kms“ l .
Eight pulsars have been discovered by NCRA astronomers using ORT. Simultaneous
observations of a few pulsars at 327MHz from Ooty and the Parkes Radio Telescope in Australia
revealed the existence of multiple diffracting plasma screens in interstellar medium in some
directions. Subsequently, an analysis of the spatial distribution of a large sample of pulsars from
the Molonglo survey was used to infer the presence of a high-electron density layer about 150
light years below the plane of the Galaxy.
RRI astronomers have carried out radio observations at 12cm mainly with the Parkes
interferometer, the VLA, and the 26m antenna at Hobart. The scientific objectives of these
studies are (i) to understand better the velocity distribution of interstellar clouds, (ii) to get a
handle on their scale sizes, and (iii) to measure distances to pulsars. An important project
undertaken with the low-frequency array at Gauribidanur was an all-sky survey at 34.5MHz, using
the method of one-dimensional image synthesis.
The low-frequency array at Gauribidanur was used by the RRI scientists to study the
characteristics of pulsed emission from about a dozen pulsars. The study includes (i) a detailed
analysis of their pulse profiles, (ii) interpulse emission, (iii) fluctuation spectra, and (iii) slow
variability. Currently a deep survey is underway with the ORT.
63
Astronomy in India: A Perspective
The radio jet in the Crab nebula has been extensively investigated. A joint Indo -Japanese
experiment to study the occultation of the Crab nebula by the moon in January 1 975 revealed that
the area emitting diffuse hard X-rays is significantly smaller than that emitting soft X-rays. This
is consistent with the synchrotron origin of X-rays. Observations of CTB 80 were among the first
to reveal its peculiar structure. It has a small-diameter (1 aremin) core, extended ridges (size
about 1°), X-ray point source, and an embedded pulsar of 30 ems period.
Thenonthermal radio source 018.95-1.1 wasshown fiomOSRT observations to be a shell-
type supernova remnant (SNR) with a central source perhaps similar to the accreting binary
SS433. It has been shown that in the case of G25 .5+0.2 (which was earlier believed to be the
youngest SNR in our Galaxy) the observed emission actually arises from stellar outflow from
what is perhaps the most massive star in the Galaxy.
A lunar occultation of the radio source Sgr A, associated with the centre of our Galaxy,
was observed by NCRA astronomers from Ooty in September 1970. With a resolution of about
one aremin at 327MHz, the observations of Sgr A provided the first details of its synchrotron
radiation revealing a multicomponent structure superimposed on a halo with a diameter of about
20pc. Attempts were made to determine the abundance of deuterium by looking for the deuterium
absorption line at 327.4MHz in the direction of the Galactic centre with ORT. These studies have
provided the best upper limits on the D/H ratio by the radio technique.
About half a degree area of the Eta Carina nebula was mapped in 1983 by the TIER
scientists in 120-300 micron band, using a ballon-borne 100cm telescope. About 30 compact
sources were detected, many of which do not find counterparts in the IRAS catalogue. Only a
few per cent of the total luminosity of OB stars in the region is radiated in the far-infrared in
contrast to young H II regions where most of the energy is emitted in the far-infrared. The young
H II region complex W 3 1 was mapped in the 120-300 micron band, as well as in the radio bands.
Eight new infrared sources were detected. It was also shown that the region is short of high mass,
high luminosity stars. Other H II region-molecular cloud complexes with deeply embedded
sources have been studied in detail.
The NCRA astronomers have made wide-field radio maps of the bright nearby H II regions
Orion A and B. The observations have been made at two wavelengths: 90cm, where the central
regions are highly opaque; and at 2.8cm, where the nebuale are fully transparent. These studies
have yielded the most accurate estimates of the electron temperatures of these nebulae from
radio continuum data alone.
An extensive survey of hydrogen recombination lines in the Galactic plane has been
carried out by the RRI astronomers using ORT. Results include discovery of large low-density
64
Research highlights
envelopes around conventional H II regions. Radio recombination lines have been systematically
observed by the RRI scientists over a wide range of frequencies (25MHz to 1 0GHz) from a variety
of objects such as H II regions, cold interstellar clouds, the warm ionized interstellar medium,
the galactic centre, nuclei of external galaxies, etc. These observations done with the ORT, the
low-frequency array at Gauribidanur, the 43m and the 93m single-dish telescopes of the National
Radio Astronomy Observatory, as well as the VLA, have been used to derive some of the
properties of different ionized regions.
To study the properties of the ionized component of the interstellar medium, an extensive
interplanetary scintillition survey of the Galactic plane was carried out by the NCRA scientists
using the ORT. The absence of sources with components smaller than 0.5 arcsec in the Galactic
central region indicates large interstellar scattering in these directions. A two-component model
for the distribution of scattering plasma and an estimate for the scattering angle as a function
of latitude were also derived from these observations.
A major research interest at IIA has been radiative transfer studies including compu-
tation of intensity and polarization line profiles in the spectra of planetary atmospheres; and
studies of line formation in extended and moving atmospheres. Scientists from TDFR have
proposed the idea of pressure dissociation in the context of stellar atmospheres and estimated
its effect. TDFR scientists have discovered CO molecule in hot B supergiants and several Be
stars. Cosmic ray excitation of the Lyman and Werner systems of the hydrogen molecules has
been shown by the TIFR scientists to produce chemically significant levels of UV photon flux
in dense clouds. Dynamical models of the formation of low-mass stars from interstellar clouds
incorporating processes such as excitation, ionization, cooling and chemical reactions have been
constructed by the TDFR scientists. Scientists from the Inter-University Centre for Astronomy
and Astrophysics (IUCAA) have been working on models of stellar and primordial nucleosynthesis
and their relationship to the observed abundances and the overall chemical evolution of the
Galaxy. Theoretical studies of pulsars are being carried out at various centres including RRI.
Galaxies and cosmology
Improvements in techniques have made it possible to study other galaxies in depth.
A photographic study of 50 Sersic-Pastoriza galaxies was carried out at IIA using the
Kavalur lm reflector. Nuclear regions of these galaxies show bright substructure due to episodes
of star formation. A classification scheme was suggested that reflects the intensity and
evolutionary stage of the star burst. The nuclear components of sizes less than 1 kpc were
65
Astronomy in India: A Perspective
distinguished from circumnuclear components of mean size 1 .5 kpc. The nucleus is often very
red, and was indentified for the first time in NGC 2903 using high-resolution I-band images. The
brightness of the nuclear and circumnuclear components in the barred galaxies in the sample
has been correlated with the length of the bar indicating the role the bar plays in the supply of
gas to the centre.
A survey of red stars in the direction of Large Magellanic Cloud (LMC) has been
completed at HA, using ultra-low resolution objective prism spectra taken at the lm reflector.
A majority of the stars are M giants and supergiants or carbon stars belonging to the LMC. B VR
H a photometry has been carried out from VBO for 1 6 1 H II regions in nine galaxies. Specific
model spectra have been constructed with a view to interpreting these observations. Comparison
of the two reveals the following: (i) The stellar component experiences lesser amount of dust
extinction compared to the gaseous components. There is also evidence for a significiant escape
of ionizing photons from the brightest regions. Both these observations indicate a clumpy
distribution of the gas. (ii) A majority of regions have undergone more than one burst of star
fromation during the last 10 million years, (iii) About 10 solar masses of gas is converted into
stars during each burst of stars fonnation. DA astronomers in collaboration with scientists from
TIER and IUCAA have observed early - type galaxies that are members of small groups,
selecting them for their radio or X-ray brightness. A majority of galaxies observed have shown
evidence of gas and dusL Studies of surface brightness of galaxies in various colours; star forming
regions in galaxies; and variability of QSOs and AGN are some of the programmes that are being
pursued in the field of extragalactic research by scientists from HA, IUCAA and TEFR.
Over a dozen extragalactic supemovae have been observed spectroscopically near light
maximum from VBO and their spectral type and their expansion velocity determined. A few
of these, notably SN 1987AinLMCandSN 1993J inM81, were monitored for longer periods.
SN 1987A wasasubluminous type II and exploded after the progenitor had made an excursion
towards blue in the H-R diagram following a red supergiant phase. IIA astronomers have
produced evidence indicating nitrogen enrichment in the surface layers. This implies CNO
cycle processing in the progenitor. The velocity structure of the outer layers was measured for
both these supemovae, and a distance estimate obtained for SN 1993J.
HA astronomers have contributed to the International Active Galatic Nuclei Watch by
monitoring NGC 3783 spectroscopically and photometrically. Search is also being made for
intra-night optical variability in radio-quiet QSOs in order to constrain theoretical mechanisms
for microvariability. Photometry has been performed on X-ray selected AGN. At HA, the
population synthesis technique has been applied to a few nearby galaxies using spectra obtained
66
Research highlights
at the European Southern Observatory, Chile. The age of the older population and the epoch of
recent star formation were determined for the galaxy NGC 5128. Other projects at IIA using
data obtained elsewhere include the study of stellar content of young star clusters in the LMC.
Numerical and analytical studies in galaxy dynamics have been carried out at Osmania
University, HA, RRI and TIER. Analytical results on ti dally interacting galaxies using impulse and
adiabatic approximations have been obtained at Osmania. Numerical work at IIA has shown them
to be in broad agreement with the N-body computer simulations in respect of merger velocities,
energy transfer and merger times. Transfer of not only energy but also angular momentum in the
case of tidal encounter between galaxies has been numerically investigated at HA.
One of the major programmes carried out with the Ooty Radio Telescope (ORT) has
been a lunar occultation survey along the moon's path in the sty. The survey yielded accurate
positions and brightness profiles for about 1000 weak radio sources with resolutions of about one
to 10 arcsec at 327MHz. Such high resolutions had not previously been attained for any large
sample of weak sources. The positional accuracy was sufficient to make reliable optical
identifications on the Palomar Sty Survey prints. The database was used to establish, for the first
time, a correlation between the angular sizes of the radio sources and flux densities, which in
turn led to the important conclusion on the evolution in physical sizes with cosmic epoch. A
significant fallout of the occultation programme was the development of a new technique of
deconvolution of occultation records. This resulted in a two-fold improvement in the resolution
achievable in obtaining brightness distributions over the conventional methods. It was one of the
first uses of the positivity constraint as an a priori information, which was later applied in the
maximum entropy methods for deconvolving radio images obtained with aperture synthesis
telescopes.
Anothermajor programme undertaken with ORT has been the observation of interplan-
etary scintillations (IPS) in the intensity of distant radio sources. These scintillations are caused
by electron-density irregularities in the interplanetary medium (solar wind). Such observations
made at different solar elongations provided valuable information both on the properties of the
medium and on fine structure (< 0.5 arcsec) in radio sources. Scintillation studies of hundreds
of sources lead to the conclusion that in the case of a large number of powerful radio sources,
a significant fraction of their flux density arises in compact (< 0.5 arcsec) hot spots in the outer
lobes. More direct estimates of the angular sizes of hot spots in a sample of 3CR radio sources
at large redshifts were subsequently obtained using VLBI techniques which showed that compact
hot spots (sizes <0.15 arcsec) were fairly common in powerful radio galaxies and quasars.
67
Astronomy in India: A Perspective
Detailed radio images of a large number of quasars at the VLA were also used to show that there
is no significant dependence of the sizes of the hot spots on either redshift or radio luminosity.
The relative strength of the hot spot however appears to increase with radio luminosity.
That compact sources (with overall sizes <10 kpc) constitute a significant fraction of the
population with steep radio spectra was first recognized from high-resolution observations with
the Westeibork Array of a complete sample from a 5GHz survey. Work by the NCRA scientists
has shown that the fraction of such sources appears to increase rapidly with redshift, which could
be related to an enhancement in the beam efficiency and to stronger confinement in a denser
interstellar medium at earlier epochs.
Some of the earliest statistical tests to explore the possibility of a 'unification scheme 7
in which the flat-spectrum core-dominated sources are the relativist cally beamed counterparts
of the lobe-dominated ones were carried out at N CRA. Several properties such as projected linear
sizes, hot spot misalignments, redshift distributions, orientation of radio polarization vectors etc.
were found to support the unification scheme. Evidence was also presented for an aspect
dependence of the optical/UV continuum emission of quasars, which implied that all optical
magnitude-limited samples of radio quasars were likely to be biased with regard to the orien-
tation of their jet axes. It now appears that both radio galaxies and quasars should be included
in an enlarged unified scheme in which they are all intrinsically similar, but objects with small
viewing angles (< 45°) are seen as quasars and those with larger viewing angles as radio galaxies.
The NCRA scientists have inferred hot spot velocites of about 0. 1 to 0.25c in double radio
sources on the assumption that the entire observed asymmetiy is due to the fact that they are
seen at different ages owing to light-travel-time effects. It has been recently shown that the
closer of the two hot spots almost always lies on the same side of the nucleus in which the
extended optical line emission has a higher surface brightness. This appears to provide the first
direct evidence that lobe distance asymmetries could be largely intrinsic in nature.In quasars
the misalignments of the hot spots on the two sides have been found not to depend on the epoch.
A three-year flux monitoring programme at 327MHz carried out using the Ooty Synthesis
Radio Telescope (OSRT) has provided fresh support for an extrinsic origin (possibly due to
refractive interstellar scintillations) of low-frequency variability in quasars. A superluminal
microlensing model has been proposed to explain the phenomenon of ultra-rapid variations (with
day-like timescales) at cm wavelengths. The bright pair 1830-21 of flat-spectrum radio compo-
nents separated by just one arcsec was discovered serendipitously by NCRA scientists in the
course of the Ooty Galactic Plane Survey, and has been interpreted as core of a distant radio
68
Research highlights
source being lensed by an intervening galaxy. Recent VLA and Merlin maps have revealed it
to be a compact 'Einstein ring'. The giant radio galaxy 0503-28 with a size of 2.5Mpc, is the largest
known radio source in the southern hemisphere, was discovered by the NCRA scientists inde-
pendently from observations with the OSRT and using the Molonglo Synthesis Telescope in
Australia. As part of an extensive study of clusters of galaxies, an ultra-steep spectrum radio
source without any obvious optical counterpart was discovered in the cluster Abell 85 by the
NCRA scientists.
The NCRA scientists have used OSRT to study the large scale structure of a number of
nearby galaxies. A multifrequency study of the edge-on spiral galaxy NGC 463 1 showed evidence
of spectral steepening with distance from the disc of the galaxy. A number of Seyfert and Sersic-
Pastoriza galaxies have been studied with high angular resolution using VLA and Merlin arrays
to look for radio evidences of starbursts and collimated ejection from their active galactic nuclei.
Several studies have been made by NCRA scientists and collaborators to determine the local
and evolving radio luminosity functions and on possible explanations for the observed
changes.Spectral measurements of the Ooty occultation sources, combined with several other
datasets, have been used to establish a statistical relation between median radio spectral indices
and flux densities of extragalactic sources found in metre-wavelength surveys. These studies
have raised doubts about the long-held view that the average spectral index was steeper at earlier
epochs.
The TEFR group is closely involved in two major programmes to optically identify and
study high redshift galaxies from Molonglo and Ooty samples. These studies have already led
to the discovery of about 25 radio galaxies at redshifts greater than two, including two at z >
3, which are among the most distant galaxies known in the universe. Observations with the ORT
have allowed interesting upper limits to be placed on the H I mass of the clusters and superclusters
at z = 3.3. As already noted, it would be possible to undertake much more sensitive searches for
H I at even higher redshifts, using the Giant Metrewave Radio Telescope (GMRT). Using the
Australia Telescope at a frequency of 8 .7 GHz, scientists at NCRA and Australia have recently
placed an upper limit of 2 x 1 0" 5 on fluctuations in the cosmic microwave background radiation
on an angular scale of about one arcmin. This is the most stringent upper limit to date on
fluctuations on this scale.
It was shown by TERR scientists that the Seyfert galaxy NGC 4945 is quite extended at
all IRAS bands, while another Seyfert, Circinus galaxy, shows only central emission. It was also
found that the extended emission from NGC4945 at 26K is cooler than the central emission at
39K.
69
Astronomy in India: A Perspective
Peer review system for fimds has not operated as rigidly in India as in the west. This has
resulted in some papers of the nonconformist kind appearing from India in reputed international
journals. Thus it is still possible in the Indian institutions to do research on alternatives to the
big bang cosmology or to question the cosmological hypothesis for quasar redshifts.
Space and high energy astrophysics
Strictly speaking, matter in this section should be distributed between the two preceeding
sections. However, for the sake of convenience, results of X-ray and gamma ray observations have
been grouped here.
In the early phase, the key objective of the hard X-ray astronomy programme at TIFR was
a detailed study of spectral and temporal characteristics of known sources like Sco X-l, Cyg X-
1, Her X-l, Cyg X-3, and sources towards the Galactic centre. Simultaneous hard X-ray and
optical observations of ScoX-1 during 1968-72 showed that the X-ray intensity in the 20-40 keV
range shows a positive correlation with the optical luminosity in the bright phase of Sco X-l.
It was also concluded that a flare results from an increase in the total mass of the hot plasma
but not its temperature. Li 1984, a temperature of kT = 6.5 ±0.9keV was deduced from Sco X-
1 X-ray spectra using a thermal bremsstrahlung model. In 197 1, Cyg X-l was shown by TIER
scientists to be one of the most chaotic and rapidly varying sources at all X-ray energies. A hard
X-ray flare was reported for the first time (subsequently verified by the PRL group and others).
The 1984 observations implied a Comptonized black-body spectrum with a plasma electron
temperature kT = 28 ±4keV. No evidence was found for any land of pulsed emission, thus ruling
out an embedded pulsar in Sco X- 1 .
The star of 1973 was the binary Her X-l. Its spectral measurement was extended to 60keV.
It was shown that the pulsed component was less than 10% of the total emission in hard X-rays.
This result was later borne out by satellite measurements. It was also shown that the origin of
the low and high energy X-rays must necessarily be the same. The source 4U1907+09 showed
(in 1985) only marginal pulsations with a period of 432.70s in the 20-80keV interval. This result
however needs to be confirmed. The 1984 observations of the X-ray pulsar GX 1+4 seemed to
imply a reversal of the spin-up of the embedded neutron star.
Rocket-borne X-ray observations have been made in the 0. 1 - 20 keV range of a number
of objects: transient sources like Cen X-l, Cen X-2 and Cen X-3; binary sources like Sco X-l
and Cir X-l, supernova remnants, as well as the diffuse X-ray background. Balloon-borne
observations in the energy range of 20-200 keV have been carried out for a number of sources
including Her X- 1 and Cyg X- 1 .
70
Research highlights
The first Indian satellite Aryabhata carried a payload consisting of X-ray telescopes in
the medium energy range 2-20 keV and the hard range 20- 150 keV. An X-ray sky monitor camera
(designed and built in collaboration with TEFR) was placed on the Bhaskara I satellite. Work is
on at ISRO for setting up an X-ray astronomy experiment (in collaboration with TIER) for
possible launch on the Indian Remote Sensing Satellite (IRS)-D2 mission. The experiment
consists of four pointed-mode proportional counters operating in the energy range 2-20 keV, and
two monitor proportional counters in the range 2-10 keV.
An experiment for studying celestial gamma-ray bursts was set up by ISRO aboaid
SROSS-C satellite launched on 20 May 1992. The experiment was aimed at measuring the
temporal and spectral evolution in gamma ray bursts in the energy range 20 keV - 3 MeV. The
experiment worked satisfactorily during the satellite's shortlife time of 54d. Another experiment
for gamma-ray studies is a part of payload of SROSS - C2 launched on 4 May 1994 (see chapter
2). An experiment was carried out by TEFR scientists to measure the diffuse gamma-ray back-
ground in 0.2-4 MeV energy range. It was concluded that the emission is of extragalactic origin.
The observed spectrum is well accounted for by a power law spectrum of index -1.8 ±0.2. A series
of balloons were flown during 1977-80 in collaboration with scientists from Moscow. It has been
shown that in the case of the Sey fert galaxy 3C 120, gamma-ray luminosity exceeds the X-ray
luminosity by a factor of 100.
Scientists from TIFR and Bhabha Atomic Research Centre, Bombay (B ARC) have studied
high energy gamma rays using the atmospheric Cherenkov arrays at Pachmarhi and Gulmarg,
and the air shower arrays at Kolar Gold Fields and Ooty. Highlight of results obtained during
the past 10 years is that some objects like the Crab pulsar and Hercules X- 1 are sporadic emitters
of gamma rays. In 1987 pulsed gamma-ray emission was detected from the radio pulsar 0355+54,
from Pachmarhi, in confirmation of theoretical predictions. That white divaifs, like neutron
stars, could also produce pulsed emission was shown by Gulmarg observations of the cataclysmic
variable AM Herculis. In various collaborative programmes,data from satellites have been
analysed. In addition there have been related theoritical studies.
TEFR scientists have measured the low but finite fluxes of Li, Be and B in the primary
cosmic radiation allowing one to deduce the path lengths of primary cosmic rays. Measurements
were made of the electron and positron energy spectra in primary cosmic rays up to a few tens
of GeV energies, with a view to understanding some aspects of acceleration and propagation of
primary co smi c rays. A qualitative estimate has been made of the charge composition of priamry
cosmic rays in the energy range 5 x 10 14 to 5 x 10 16 eV by simultaneous observations on electrons
at the suface and on muons underground at the Kolar Gold Fields in extensive air shower
experiments.
71
Astronomy in India: A Perspective
General relativity and gravitation
Work in the 1940s and 150s included well known contributions by P.C. Vaidjya ( 1944) and
A.K.Raychandhuri (1955). By and large, work in general relativity in India has involved solving
differential equations to find exact solutions of Einstein’s equations and studying some geometri-
cal aspects of the theory. This work is being carried out at various centres including colleges
and universities. There have come important contributions to gravitation theory and cosmology,
including studies of black holes.
The perturbations of black holes in normal as well as in quasi-normal modes have been
studied at RRI, IUCAA and HA. The scalar perturbations of spherically symmetric black hole
solutions in theories with quadratic Gauss-Bonnet corrections have also been investigated.
Charged particle trajectories around black holes in vacuum as well as in magnetic fields have
been studied by several authors at PRL, IUCAA, Indore and Ravishankar Universities. It has been
shown at IUCAA that the criterion for corotation should be redefined relative to a locally
nonrotating observer so as to avoid conflict with the second law of black hole physics and the
conservation of energy. An attempt was made at TIFR to define a black hole in an expanding
universe.Workers at IUCAA and the University of Poona have considered the effect of rotation
and magnetic field on the shape of the event horizon of a black hole. In the spirit of the Gauss
theorem, the gravitational charge of a rotating black hole has been defined and applied to a black
hole in a magnetic field.
Modem techniques have been employed at TIFR to study the type of matter distribution
in the physical universe that is allowed by general considerations of global hyperbolicity and
causality. Quantum effects on space-time singularities of general globally hyperbolic space-
times have been investigated at TIFR, leading to the conclusion that some non-singular states
are also probable. Linearization stability of the solutions of Einstein’s equations has been
demonstrated by workers from TIER and Bhavnagar and Nagpur Universities. Works on the
extent of validity of the cosmic censorship hypothesis is going on at TIFR and Aligarh Muslim
University.
Scientists at IUCAA and TIFR have done pioneering work in the area of quantum gravity
by quantizing the conformal degree of freedom and studying its cosmological effects. In this
restricted treatment it is shown that quantum effects will force the universe to avoid the big bang
singularity. Quantum field theory in curved space-time, semiclassical calculations in space-
times of interest and the application of results from particle theory to cosmology including
inflation have been considered by several workers.
72
Research highlights
The existence and relevance of dark matter in astrophysics and cosmology was first
published in 1972 in a collaborative study from TIFR. The proposal was that weakly interacting
particles with a finite rest mass (neutrinos) left over from the big bang would constitute a
gravitating background of invisible matter; these would trigger the formation of galaxies and
would explain the discrepancy in the virial masses of galactic systems . In the mid 1980s, there
was a spurt of activity on this topic and several workers considered dark matter of various types.
Cosmological implications of cosmic strings are being considered at TIFR and IUCAA. A major
effort on data analysis of gravitational waves in various detecting systems is currently under way
at IUCAA. The signal-to-noise analysis including the photon counting noise and thermal noise
has been made for an array of five, four and three detectors.
The properties of a thin accretion disc around a rotating black hole in a magnetic field
have been considered at PRL and Ravishankar University. The magnetohydrodynamics around
rotating black holes has been extensively studied at TIFR. By taking into account the presence
of magnetic field around a rotating black hole, scientists at IUCAA have revived the Penrose
process of energy extraction as a viable mechanism for powering the central engine in active
galactic nuclei and quasars . The capture of gravitational neutrinos has been extensively studied
at RRI. Scientists at DA and Delhi University have studied gravitational red shift and spectral
line broadening of radiation from a rapidly rotating pulsar by taking the Kerr metric to represent
the pulsar. A suggestion to consider white holes as a source of high energy radiation was also
studied at TIFR, IIA and Poona University in the 1970s. The gravitational bending of a light ray
gives rise to the astrophysically interesting phenomena of gravitational lensing and superluminal
separation of VLBI components in quasars. Considerable work has been done in this important
area at TBFR and RRI.
73
4
Promotional activities
1 here is now in the country a sizeable number of professional astronomers and space
scientists. A number of learned societies coordinate their activities at various levels. Activity
at the amateur level is also on the rise.
National Academies
International relations in astronomy are overseen by the Indian National Science Acad-
emy through its National Committee for the International Astronomical Union. Research projects
on history of astronomy can be funded by the academy through its Indian National Commission
for the History of Science, which also publishes the Indian Journal of History of Science. Indian
Academy of Sciences, Bangalore, brings out a quarterly Journal of Astrophysics and Astronomy
as a vehicle for publication of results in modem astronomy.
Indian Astronomical Society
Meghnad Saha’s idea of forming an Indian Astronomical Society could take shape only
a few years after his death in 1956. The Society was registered on 24 September 1959. It was
inaugurated in December 1960 under the chairmanship of A.C.Baneqee, but for some reason the
Society’s work came to a halt by 1963. It was revived in 1974. The first elected council was
formed in 1977 with N.C.Lahiri as President and B.N.Basu as Secretary. Since 1986, the Society
has an office in the Department of Applied Mathematics, Calcutta University. The Society
started the publication of its journal XfaisA in 1980. The name was changed to Mahavisva in 1982.
As the registration of the journal was delayed for several years, a new series was started with
Volume 1 in 1988. The Society holds national and international seminars and symposia. It also
conducts summer and winter schools on basic astrophysics, and arranges popular lectures by
eminent Indian and foreign scientists.
74
Promotional activities
Astronomical Society of India
In 1970-71, a questionnaire was sent to about 150 scientists to seek their view on the need
for setting up an all-India astronomy forum. About 100 of them responded, all except two
supporting the idea. Accordingly, the Astronomical Society of India enrolled its first member
on 25 October 1972; another 20 joined on 14 November. The Society was formally registered on
19 January 1974, with its office in the Astronomy Department, Osmania University, Hyderabad.
The first meeting was held in March 1974, when its memorandum and bye-laws were passed.
The first President and Secretaiy were M.K. V Bappu and K.D. Abhyankar. The Society has on
its rolls 284 regular members, including 208 life members, 88 associate members, seven insti-
tutional members, and one donor member. Honorary fellowship has been conferred on
S. Chandrasekhar, (late) Z.Kopal, (late) D.S.Kothari, R.Hanbuiy Brown, and A.K.Raychaudhuri.
The Society has been publishing a quarterly journal. Bulletin of the Astronomical Society
of India, since 1973, and exchanging it with a number of corresponding societies in Australia,
Britain, Germany, countries of the former Soviet Union, and the U.S.A. The Society offers an
award for the best paper published in the Bulletin by authors below 35.
The Society meets about twice in three years. The programme usually consists of invited
talks, contributed papers, special sessions on topics of current interest, and popular lectures. Very
often, a seminar or a symposium is held in conjunction with the scientific meeting. A limited
number of travel grants are offered to enable research workers to present their results at the
meetings. The Society also runs a programme by which interested amateurs, mostly school and
college students, are sponsored for visits to astronomical centres. The Society has instituted an
international award, called Vainu Bappu Memorial Award, after its first President, to be given
to astronomers (normally below 35) who have made exceptional contribution to any branch of
astronomical sciences. The medallists include Yasuko Fukui (Nagoya University, 1986),
Shrinivas R. Kulkami (California Institute of Technology, 1988), and George P.Efstathiou (Uni-
versity of Oxford, 1988).
Indian Association for General Relativity and Gravitation
In February 1969, Indian relativists met in Ahmedabad to felicitate their doyen,
V.V.Narlikar, on his 60th birthday. It was decided at the meeting to setup the Indian Association
for General Relativity and Gravitation (IAGRG) with V.V.Narlikar as the President and JLKrishna
Rao as the Secretary. IAGRG has a membership of about 1 80. It brings out a news bulletin called
Gurutva, and holds scientific meetings at an average interval of a year and a half. IAGRG
75
Astronomy in India: A Perspective
manages the Vaidya-Raychaudhuri Endowment Fund established in 1986. Since 1989, the Fund
has been used to hold a Vaidya-Raychaudhuri Lecture by a distinguished scientist, at every
IAGRG meeting.
In the early 1980s, at the initiative of some of the Association members, the University
Grants Commission formed a National Coordinating Committee on Relativity and Cosmology
to foster the growth of these subjects in the University departments of physics and mathematics.
The Committee coordinated activities in this field for the Commission, including orientation
programmes for teachers and advanced-level workshops for research workers. Now the Committee
has been dissolvewd and its activities entrusted to the IUCAA.
IAGRG co-sponsored the Einstein Centenary Conference in 1979 at the Physical Research
Laboratory, Ahmedabad. In the mid 80s, the Association started a four-yearly series of Interna-
tional Conferences on Gravitation and Cosmology. So far the conferences have been held at Goa
(1987) and Ahmedabad (1991). The 1995 conference will be held at the Inter-University Centre
for Astronomy and Astrophysics, Pune.
Amateur and popular astronomy
The ‘old ever-young' science of astronomy commands an enthusiastic band of followers
at the popular as well as amateur level. According to a rough estimate there are about 400
telescopes of about 10- 15cm aperture in the hands of individuals and public institutions. There
are about 40 active astronomy clubs in the country, some of which have been in existence for
as many as 50 years, e.g., the Jyotirvidya Parisamstha, Pune. Many bring out informative
newsletters, based on material published elsewhere. In addition, a fairly large number of popular
books are written in Indian languages, especially Bengali and Marathi. Many of these books are
the only authentic source of astronomical information for their readers.
Expectedly, there is a great demand for telescopes whenever comets and eclipses hit the
news headlines. Most astronomy buffs are content with viewing the celestial object with their
eyes; only a handful seek to preserve the image on a photographic film. Most amateur work has
tended to be picture postcard type rather than research publication type. Conscientious efforts
are being made by astronomical research centres to motivate amateur astronomers, especially
students, to make reliable observations and communicate their results to professional channels.
Amateur organizations are being offered support in terms of funds, equipment and resource
personnel by various research institutions. A number of workshops on making small telescopes
have been held under professional auspices, although lack of easy availability of good quality
76
Promotional activities
glass blanks remains a problem. IUCAA has already created a cell for promoting amateur and
popular astronomy and organized pedagogical and do-it-yourself workshops for amateurs and
teachers of astronomy.
Initial steps have been taken to form a National Federation of Amateur Astronomers.
Future plans for amateurs aim at introducing them to measurement astronomy. A number of
schemes suggest themselves: making a variety of project-oriented photometers for use by
amateur astronomers; development of low-cost automated drives for small telescopes; making
available user-friendly reference material at low cost; and providing a refereed channel for
publication of their results.
Popularization of astronomy takes place at various levels: print and electronic media,
efforts by professional institutions, and planetariums. The government of India organizes science
exhibitions all over the country, in which most institutions participate. Every year, 28 February
(the date Raman discovered his effect) is celebrated as the National Science Day, when all
scientific institutions keep open house. Observatories at Kavalur, Kodaikanal, and Naini Tal
have earmarked small telescopes for use by visitors. Indian Institute of Astrophysics has produced
two video films, on the 1 980 solar eclipse and on Kavalur and Kodaikanal Observatories. It also
video-recorded, in 1989, an interview with Prof.S.Chandrasekhar. India Meteorological Depart-
23. The planetarium at New English School, Pune. Set up in 1954, it is the oldest in the countiy.
77
Astronomy in India: A Perspective
menfs Positional Astronomy Centre, Calcutta, as part of its official duties, makes available sky
charts and almanacs at a nominal price.
Thereareatpresent30planetariumsinthecountiy. The first planetarium in India was
opened as early as 1954 in the New English School, Pune. Called Kusumbai Motichand
planetarium, it was supplied by Spitz Laboratories, Philadelphia, U.S.A., at a total cost of
Rs 35000. It owes its installation to the creative urge of an architect. The plan for the new
school building included a 30 foot diameter, three-storey high dome, as a roof for the central
hall. Given the dome, it was natural to think of a planetarium which became a reality thanks
to a generous donation of Rs. 50000 by Motichand Shah in memory of his wife.
The next planetarium in India was the Birla planetarium at Calcutta set up in 1962.
It was followed by Sardar (Vallabhbhai) Patel Planetarium at Baroda (1976) and Nehru Plan-
etarium, Bombay- Worli (1976), Jawahar Planetarium, Allahabad (1980), Nehru Planetarium,
New Delhi (1984). Other cities with planetariums are Bangalore, Bhubaneswar, Bombay-
Powai,CaIicut, Gorakhpur, Guwahati, Hyderabad, Jaipur,Lucknow, Ludhiana, Madras, Manipal,
Muzaffarpur, Nagpur JPatna, Porbander, Puttaparthi, Rajkot, Salem, Srinagar, Surat,
Thiruvananthapuram, Vijayawada, and Warangal.(A few of these are not yet open to public.)
Many planetariums in India are named after Jawaharlal Nehru, whose Glimpses of World History
quotes [Sir] James Jeans on the expansion of the universe. His call for inculcation of "scientific
temper" constitutes the main point on the planetarium agenda. Planetariums are in general well
equipped with the tools of the trade: models, graphics and software. They attract visitors from
all age groups, but school children are specially targetted. There are introductoiy classes in
astronomy, public lectures, and quiz and essay competitions for them.
Popularizing astronomy without trivializing it and conveying the rigour of science with-
out intimidating the audience remain a challenging task.
78
Directory of addresses
Astronomical Society of India
C/o Department of Astronomy
Osmania University, Hyderabad 500007
Phone (40) 868951
Decameter-wave Radio Telescope
(Raman Research Institute)
(Indian Institute of Astrophysics)
Gauribidanur 561210, Kolar Dist, Karnataka
Phone (8 155) 8625
Department of Astronomy
Osmania University, Hyderabad 500007
Phone (40) 868951
Department of Astronomy & Space Sciences
Punjabi University, Patiala 147002, Punjab
Phone (175) 822161 extn6301.
Telex 394 219 PUP IN
Gravitation Experiment Laboratory
(Tata Institute of Fundamental Research)
BARC Seismic Array Station
Gauribidanur - Hosur 561208
Kolar Dist, Karnataka
Phone (8 155) 2262
High Energy Gamma Ray Observatory
(Tata Institute of Fundamental Research)
AmrakBhavan, Pachmarhi 461881
Madhya Pradesh
Phone 2113 (via Jabalpur or Bhopal)
Indian Academy of Sciences
C.V.Raman Avenue, Post Box 8005,
Sadashivanagar, Bangalore 560080
Phone (80) 3342546, 3344592. Fax (80) 3346094.
Telex 845 2178 ACAD IN
79
Astronomy in India: A Perspective
Indian Astronomical Society
C/o Department of Applied Mathematics
Calcutta University
92 Achaiya Prafulla Chandra Road
Calcutta 700009
Indian Institute of Astrophysics
Saijapur Road, Koramangala, Bangalore 560034
Phone (80) 5530672, 5530583. Fax (80) 5534043, 5534019
Telex 845 2763 DAB IN. E-mail root@iiap.emet.in
Indian National Science Academy
Bahadur Shah Zafar Marg, New Delhi 1 1 0002
Phone (1 1) 33 13 153, 33 12450. Fax ( 1 1) 3716648.
Telex 3 1 61835 INS A IN. E-mail xxxx!vikram!insa!root
Inter-University Centre for Astronomy & Astrophysics
Post Bag 4, Ganeshkhind, Pune 4 1 1007
Phone (212) 336415, 336416. Fax (212) 335760.
Telex 145 658 GMRT IN. E-mail root@iucaa.emet.in
ISRO Satellite Centre
Vimanapura, Bangalore 560017
Phone (80) 5566251. Fax (80) 5567621,5567544.
Telex 845 2325. ISACIN. E-mail root@isro.emet.in
Joint Astronomy Programme
Department of Physics, Indian Institute of Science, Bangalore 560012
Phone (80) 3344411. Fax (80) 3341683. Telex 845 8349
Kodaikanal Observatory
(Indian Institute of Astrophysics)
Kodaikanal 624 103, Tamil Nadu
Phone (4542)217, 643
Mauritius Radio Telescope Project
Faculty of Science,
University of Mauritius
Reduit, Mauritius.
Phone (230) 4237804, 4541 04 1 . Fax (230) 4549642
Telex 966 4621 UNIMIW. E-mail root @ fl.n726.z5.fidonet.org
80
National Academy of Sciences, India
5, Lajpatrai Road, Allahabad 21 1002
Phone(532) 641183, 64022
National Centre for Radio Astrophysics
(Tata Institute of Fundamental Research)
Post Bag 3, Ganeshkhind, Pune 41 1007
Phone (212) 333384, 336111.Fax (212) 345149
Telex 145 7658 GMRT IN. E-mail root@gmrtemet.in
Nuclear Research Laboratory
(Bhabha Atomic Research Centre)
Trombay, Bombay 400085
Phone (22) 5564225. Fax (22) 5560750, 5560534
Telex 116 1017, 116 1022BARC1N.
E - mail root® magnum, bare tl.emet.in
Physical Research Laboratory
Navrangpura, Ahmedabad 380009
Phone (79) 462129. Fax (79) 460502.
Telex 121 6397 PRL IN. E-mail root@prI.emet.in
Positional Astronomy Centre
(India Meteorological Department)
P-546 Block N, 1st floor
New Alipore, Calcutta 700053
Phone (33) 4780321,4783541
Raman Research Institute
C.V. Raman Avenue, Sadashivanagar, Bangalore 560080
Phone (80) 3340122. Fax (80) 3340492.
Telex 845 267 1 RRI IN. E-mail root@rri.emetin
Radio Astronomy Centre
(Tata Institute of Fundamental Research)
Post Box 8, Udhagamandalam 643001, Tamil Nadu
Phone (423) 2032, 4049. Fax (423) 2588. Telex 850 4208 RAC IN
Tata Institute of Fundamental Research
Homi Bhabha Road, Colaba, Bombay 400005
Phone (22) 2152971, 21523 1 1. Fax (22) 2152110.
Telex 118 3009 T1FR IN. E-mail root@tifrvax.bitnet
81
Astronomy in India; A Perspective
Udaipur Solar Observatory
11 VidyaMarg, Udaipur 313001,
Phone (294) 60626, 60427. Telex 335 223 USO IN
E-mail uso@prl.emet.in
Uttar Pradesh State Observatory
Manora Peak, Naini Tal 263 129,
Phone (5942) 2136, 2583
Vainu Bappu Observatory
(Indian Institute of Astrophysics)
Kavalur 63570 1, North Arcot Ambedkar Dist, Tamil Nadu
Phone 222, 255 (via Vaniyambadi)
(This is a partial list of organisations interested in the advancement of astronomy and astrophysics. It
is a matter of satisfaction that the list is steadily becoming longer.)
82
Index
Achyuta Pisharati 2-4
Airy, George Biddel 10
Akash 74
A1 Biruni 2
American Association of Variable Star
Observers 22
Aryabhata 11,3
Aryabhata II 3
Astronomical facilities
Ahmedabad42
Bangalore 41, 44
Bombay 42, 47
Gauribidanur 4 1 ,5 1
Gurushikhar 34
Hyderabad 31
Japal-Rangapur 31'
Kavalur 28
Khodad 40
Kodaikanal 35
Naini Tal 33
Ooty 38-39
Pachmarhi 49
Pune 38, 49
Thaltej 42
Udaipur 36
Udhagamandalam 38-39
Astronomical Society of India 21, 75
Astronomy
Amateur 76
Gamma-ray 46
Modern 9
Optical 28
Physical 15
Popular 76
Radio 37
Siddhantic 1
Space 42
Zij 6
Banerji, A.C. 26
Banerji, S.K. 26
Bappu, Manali Kallat Vainu 22, 25, 28, 75
Bhabha Atomic Research Centre,
Bombay 47-48
Bhabha, Homi Jahangir 25, 27, 45
Bhagvantam, S 26
Bhaskara 11,5
Bhaskara II 1, 3-5
Bhaskaran, Hieralandoor
Panchapagesha20
Bhaskara Shastri T.P. 20, 26
Bhattotpala 1
Bose, Satyendra Nath 23, 24
Brahmadeva4
Brahmagupta 1-4, 6
British Association for the
Advancement of Science 14
Broun, John Allan 14
Browning 14
Bulletin of Astronomical Society of India 75
Caldecott, John 14
Carte du Ciel 19
Chakradhara7
Chakreshvara Mahadeva 4
Chandra, Radha Gobinda 1 1
Chandrasekhar Simha, Samanta 3, 5
Chandrasekhar, Subram anyan 24-25
Charry, Chintamani Ragoonatha2, 13
Chatwood, Arthur Brunei 19
Chhatre, Kero Lakshman 2
Chintamani Dikshit 7
Chitrabhanu 4
Christie, W.H.M. 18
Clarke, Agnes 24
Cook, Captain James 10
Cooke 20
Dadabhai Bhatta7
Dallmeyer, John Henry 18
Datt, B. 5, 24
Datta Majumdar, S. 25
Decameter-wave Radio Telescope 14
Devaeharya4
Dhar, NagendraNath 22
83
Dhundiraja4
Dinakara4
Dixon, Jeremiah 11
Dollond 10, 11
Elmer-Chandra Telescope 22
Elmer, Charles W. 22
Evershed, John 18-19, 25, 27, 35
Ferozshah Tughlaq 6
Gamma-ray Telescope 47
Ganesh Daivajna 2, 4, 7
Garga 1
George V, King 9
Gravitation, Experimental 5 1
Grubb 16, 19,20, 35-36
Gurushikhar Infrared Observatory 34
Gurutva 75
Hale 20, 35
Halley, Comet 21, 27
Haridatta4
Herbert, James Dowling 14
Hitler, Adolf 22
Indian Association for the
Cultvation of Science 20, 21
Indian Association for the
Gravitation and General Relativity 75
Indian Astronomical Society 74
Indian Institute of Astrophysics 28, 35, 41
Indian Journal of History of Science 74
Indian National Science Academy 20, 24
Indian Space Research Organization,
Bangalore 44
Instrumentation Texts, Table 3
Inter-University Centre for Astronomy and
Astrophysics, Pune 49
Ishaque, M 26
Ishvara4
Jacob, William Stephan 14
Jagannatha 6, 7
Jambusara Vishrama 7
Jai Singh Saw^ai, Raja 6, 9
Jantar Mantar 8
Japal-Rangapur Observatory 3 1
Jatadhara 5
Javahar Singh 6
Jnanaraja 3
Journal of Astrophysics & Astronomy 74
Jugga Rao Bahadur, Raja A.V. 23
Juggarow, Code Venkata 22
Kanaka 2
Kanak al - Hindi 2
Karanas 1, 2, Table 2
Ketkar, Venkatesh Bapuji 3
Kodaikanal Observatory 3,14, 18-19, 25-27, 35
Kothari, Daulat Singh 24, 26
Krishna 5
Krishnan, K.S. 26
Kumar Kanti Chandra Singh
Bahadur 21
Lafont, Fr Eugene 16, 20
Lagadha 1
Lakshmipati 7
Lalla 1, 3
Lassel, William 14
Latadeva 1, 3
Laue, Von 24
Lerebours & Secretan 1 1, 14, 18, 35
Lockyer, Joseph Norman 15, 18
Madras Catalogue 10
Mahadeva4
Mahavisva 74
Mahendra Suri 6, 7
Malaviya, Pandit Madan Mohan 24
Manjula 1, 4
Mason, Charles 10
Mathuranatha Shukla 7, 8
Mauritius Radio Telescope 41
Merz-Browning 21
Michie Smith, Charles 18
Millimeter-wave Telescope 4 1
Mukeijee, Kalinath 37
Munjala 1,4
Naegamvala, Kavasji
Dadabhai 16, 18
Nagesha4
Nandarama Mishra 2, 5, 7
Narayan, A.L. 26
Narlikar, Vishnu Vasudeva 24, 75
Nasir al Din al Tusi 6
84
National Centre for Radio Astrophysics,
Pune 38
Nature 23
Nizamiah Observatory 19, 27, 3 1
Nehru, Jawaharlal 25, 78
Norgay, Tenzing 23
Nuclear and High- Altitude Laboratories
(BARC), Bombay 47
Nursing Row, Ankitam Venkata 22
Ooty Radio Telescope 38
Ooty Synthesis Radio Telescope 39
Observatories, Old
Colaba 2
Daba Gardens 22-23
Dehra Dun 15
Delhi 6
Jaipur 6
Lucknow 14
Madras 2, 9-11, 13-14
St. Xavier's College, Calcutta 15- 16
Takhtasingji 16-18
Trivandrum 11-12,14
Padmanabha7
Parameshvara 1-2, 4
Petrie, William 9,10
Physical Research Laboratory,
Ahmedabad 34, 36, 42
Piazzi Smyth, Charles 1 1
Planetariums 77-78
Pocock, Robert John 19
Pogson, Norman Robert 14, 18
Positional Astronomy Centre, Calcutta 25
Putumana Somayaji 5
Prithudaka 1
Ptolemy 6
Ramanchandra 7
Ramachandra Bhat 4
Raman, Chandrasekhar Venkata 2 1 , 26
Raman Research Institute, Bangalore 40
Raychaudhuri, Amal Kumar 24
Research highlights, Ch3
Galaxies and Cosmology 65
General relativity and gravitiation 72
Solar system studies 58
Space and high energy astrophysics 70
Stars and the galaxy 59
The sun 53
Richaud, Jean 9
Royal Astronomical Society 22
Royal Society 27
Saha, Meghnad 23-26, 74
Sampumanand Telescope 33
Saranis 2, 3
Sen, Nikhil Ranjan 24
Shakerley, Jeremiah 9
Shankara5
Shankara Variyar4
Shankara Varma5
Sharvishtha 1
Shelton, John 20
Shripati 1,3-4
Siddhantas 1-2, Table 1
Sircar, Dr Mahendra Lai 20
Statesman ; The 23
Steinhill 16
Strobel, Andre 6
Suraj Mai 6
Swarup, Govind 25
Tata, Dorab 25
Tata Institute of Fundamental Research 25, 38,
42, 49
Tata, Jamsetji Nusservanji 18, 24
Taylor, Thomas Glanville 10, 22
Telescope
Decameter-wave Radio 41
Elmer-Chandra22
Gamma-ray 47
Giant Meter-wave Radio 40
Mauritius Radio 41
Millimeter- wave 4 1
Ooty Radio 38
Ooty Synthesis Radio 39
Proposed National Large Optical 37
Sampumanand 33
Vainu Bappu 28
Tennant, James Francis 15
Tomkins, Herbert Gerald 21
Topping, Michael 9-10
Transit of Mercury 9, 22
Transit of Venus 9, 13, 15, 22, 27
85
Troughton & Simms 14
Turner, Herbert Hall 19
Udaipur Solar Observatory 36
Uttar Pradesh State Observatory',
Naini Tal 33
Vaidya, Prahlad Chunilal 24
Vainu Bappu Observatory, Kavalur 28
Vainu Bappu Telescope 28
Varahamihira 1, 4
Vararuchi 4
Vateshvara 3
VedangaJyotisha 1
Vince R.S. 2
Vishnu 4
Zafar Jung, Nawab 19
Zij al-Sindhind 2
Zij -e-Muhammad Shahi 6
Zizes6
86
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11